I suspect most Bandlab users don't think about "genres" at all. They think they are making music, period. So if they even notice that they are being asked to categorize their sound, they might not know how to do that, or they might not want to be bothered. When I was starting out (right after the Civil War) the goal of every young songwriter was to get on the radio, but it still took me a couple of years before I saw that radio was extremely segmented, and your music had to fit a segment (genre) or program directors wouldn't listen. Today, radio holds very little sway. The gatekeepers don't have much power, and the kids starting out don't know (and don't need to know) rap from reggae. There are too many of them to moderate, and algorithms won't get it.
Bottom line: We are the legacy SONAR users, the last of the old guard. We use the DAW the way recording studios used to be used. The new generation doesn't. Bandlab has rudimentary tools and loops online, and even though they can get SONAR for free now, I'd be surprised if more than 20% of them try it. And they don't care about no stinkin'
genres. Maybe instead of having to wade through many, many tracks that are mislabeled or just plain wrong,
the Bandlab site could have a section devoted specifically to those trying to find partners to work with, like a musician's contact service, with an online form allowing you (us) to say what we do and what we're looking for, with "genre" being a required field.