Hey @everybody, thanks for joining the debate! This is what I’d been hoping for.
Let me get to your arguments one by one.
You’re welcome. My pleasure. 
Also @wechselgeruecht: With respect to the question of abolishing 50+1 and allowing freedom of investment to combat the undesired accumulation of capital effect at the biggest clubs, I might refer you to this thread Forsetzung der Diskussion aus Schlusskonferenz 216 - #25 - #4 von Albulipe, where @Chryshie @Christian_Jakob and I have already debated this point. I am aware that there is a language barrier because I write in English, but if you are not averse to reading English, please feel invited to catch up on the discussion over there. You might find it interesting.
In short, in my opinion, there are just two ways to succesfully close the gap between the rich and the poor clubs: either a radical redistribution of TV and broadcasting revenues by the DFL or a complete freedom of investment (entailing an elimination of 50+1) with concurrent temporary suspension of UEFA FFP so that investors can quickly pour a lot of money into their clubs without the danger of facing charges for violating FFP by the UEFA.
By the way, I sympathise with your ideal of people and organizations adhering to the spirit of the law, not just the letter. In my own private ideal world, everybody would do this too. Alas, I am a realist. And as such I cannot fault Red Bull and RB Leipzig for exploiting the 50+1 rule to its limits. The DFL knows this too, of course, they are not stupid. Hence I would rather fault them for either not adjusting their rule to put an end to Red Bull’s actions, or for silently accepting and condoning what Red Bull is doing. Which of the two alternatives you find less savoury, I leave up to you.
Are you sure? I have tried to find this rule online to no avail. Could you point out to me where to find this in the official DFL/UEFA rules?
Fair enough. There is some truth to that and I sympathise with you. However, at least for the time being, spectator attendance figures don’t show that the Monday night game suffers from its allegedly inconvenient date and time. Attendance has been good and for my taste, the downside of some 20-30,000 odd fans having to travel on a Monday night is more than made up by the upside of increased potential revenues by additional domestic and foreign media coverage (which in the end benefits all clubs, don’t forget).
On to the next topic. To support your stance against investors, you offer three major lines of argumentation.
First, you say that there are some investors who just use their clubs as vehicles to promote a product (like Red Bull). So what? What’s so wrong about this? Why does it matter to you for which reason an investor puts money into a club? Red Bull wants to promote a soft drink, okay, but what do you think all the investors and sponsors at other clubs want? Unless they’re patrons or big time donors without any self interest (thanks @wechselgeruecht), such as maybe Dietmar Hopp who might actually really be giving money to his TSG just for the sake of strengthening the sporting profile of his region and the love of football in general, they all want something in return for their investment. Brand recognition, financial returns, creating a positive image for themselves etc. You name it. I don’t know what your club is, but do you think that e.g. the Commerzbank with Frankfurt or Signal-Iduna with Dortmund have fundamentally different goals than Red Bull?
This is just part of the intrinsic nature of any economic relationship. It is based on exchange. Giving and getting. Tit for tat. If you, @alxalix are well off and have a daughter who is about to go to school and you give money to that school so that it may repair its roof, do you think it matters to that school whether you give the money out of the pure kindness of your heart or because you hope that your daughter will have a better school experience? I think not. They will be happy either way. And even though this might not be entirely in keeping with Kant’s definition of moral acting (do the right things for the right reasons) I think that it should be so, shouldn’t it? As long as the money you give to that school and the money Dietrich Mateschitz gives to RB Leipzig is not gained by criminal means, the motives shouldn’t matter. Life is not a seminar on moral philosophy.
Second, you don’t like the Red Bull investment because it entails a specific way of playing football (aggressive, high tempo, pressing intensive, vertical attacking football) which supports their brand and product image. So what? What is it to you whether RB Leipzig plays the way it plays because of Red Bull or because of anything else? By the same standard you could just as well criticise every other club for playing the way they do. Why is playing in a certain way morally inferior when it happens under orders of Red Bull to when it happens because any given coach or sporting director says so?
On the contrary, shouldn’t you rather praise Red Bull and RB Leipzig? Do we as discerning fans not frequently complain that clubs often enough don’t have a clear vision and strategy of how to play and which players and coaches to hire? Arguably, RB Leipzig is one of the very few examples of a club who actually has a consistent vision and long term strategy and does implement it on the pitch and when they sign new players. I, for one, do praise RB Leipzig for that. I like what they are doing. I like the vision, I like the commitment, I like the single-minded focus, I like the dedication. And whether that’s because Red Bull wants it that way or because the moon is 300,000 km away from Earth, I don’t care. And neither should you unless you consider yourself the ultimate arbiter of moral judgement (which I hope you don’t).
Third, you say that some investors have ruined their club. That’s true but you extrapolate from some to all. Because some investors are bad, the idea of allowing investors in general is bad. I don’t do it the other way around. I don’t say because some investors are good, all investors are. The difference between the two of us is that I take the positive moral approach and you the negative one. I am saying: allow investors in general and trust the clubs to make a sensible decision for themselves on a case by case basis (do we want this particular investor or not?). You want to preclude this option altogether. Slippery slope and so on, I suppose. I am a liberal person. I have great trust in the faculty of men to make sensible decisions for themselves. Moreover, I am a pragmatist. Allowing investors to invest freely would at least give poorer and lower class clubs a chance to catch up to the bigger ones (which otherwise will remain very difficult because of the aforementioned accumulation effect of money).
Fair enough. Agreed. It is just that this small minority is, at the same time, the most visible part of the fans. And unfortunately, it seems to me watching on TV at home that the great majority who doesn’t think and act this way at least does nothing to prevent their vitriolic banners and violence in the stands. I know, it is easier said than done, I would be afraid too, but still…
In addition, even though only as small minority of fans resort to violence to make their views known, I am sure the great majority of the fans has a clear understanding of what they consider right and wrong. And it is obvious to me that this view is based on a set of convictions that’s arbitrary, self-serving and intellectually lazy. It is because I am so fed up with and annoyed by this that you might get the impression that I am one-sided and hold rather extreme views.
With respect to all these points, I also recommend reading all of @wechselgeruecht’s statements. I more or less agree with him on most things.
@Chryshie: I apologise again if I have appeared one-sided. That wasn’t my intention! 
BTW, what exactly is Red Bull doing in Brasil? I am curious, too.