Worth noting that German clubs are somewhat unique because they're supposed to be owned by the fans[0], not corporations (with some exceptions). Fans pay money for the membership to have some influence on its operation and vote on some issues.
As one can see from your link, it's definitely less than perfect in practice, but that's why the fans are supposed to have any say in deals like this instead of the club being able to do whatever they want to like in most other countries.
I listened to a news podcast that covered the meeting[0] and it was very interesting to hear the fans chanting "We are Bayern, You are not!"
Turns out the club bylaws put sponsorship decisions entirely in the hands of the leadership, and this was affirmed in court, so there's no way for the fans to cancel the Qatar deal without convincing the very people who made the deal.
Doesn't the leadership have terms and need to be reelected? At least that's what happens with clubs here. As an associate, you can vote on the next president.
As one can see from your link, it's definitely less than perfect in practice, but that's why the fans are supposed to have any say in deals like this instead of the club being able to do whatever they want to like in most other countries.
[0] https://en.m.wikipedia.org/wiki/50%2B1_rule