I hate being "that guy", but isn't nearly every private corporation's policy "guilty until maybe proven innocent"? If Chuck E Cheese's get a report that I an punching children to death, they might preemptively disallow me in even if there's no evidence supporting that claim. If one of Best Buy's employees accused me of stealing Blu-Rays, they might not allow me into the store, even without any evidence. If I were a director and there was a rumor that my goal was to get Universal sued, they might not bring me on as a director.
I'm not saying that this is should be how it is, and you could make a strong argument that it shouldn't be this way, but I think it predates YouTube.
Chuck E. is not the dominant platform for sharing video online. As the internet has replaced the town square people have come to expect a higher duty from the dominant internet companies than profit motive. The law hasn't kept pace with our expectations of these new quasi-public spaces.
But how exactly do we draw the line of what's acceptable with YouTube? Should YouTube be forced to host hardcore porn [1]? If not, why not? You could say "well anything that the FCC allows", but then that means we'd have to disallow most videos that have curse words in them (not to mention it would greatly reduce the appeal of YouTube for me, since part of why I like it is because it allows stuff that wouldn't be allowed on TV), but if you're saying that YouTube should be a free-speech zone, then how exactly is porn not protected speech?
I'm not claiming I have the answer, but I feel that the vague "omg youtube is a platform so it should allow all my videos!!!!" argument is extremely reductive, and tends to imply that it should just be this total anarchy of a platform. If YouTube doesn't regulate their content, it's going to be hard to find advertisers, and if they can't find advertisers it will be hard to monetize the platform.
[1] Obviously legal stuff, porn that's outright illegal should of course not be allowed.
An actual town square is a scarce resource (due to being a physical piece of real estate) that's usually managed by a municipality in a way that ensures fair access.
Online video sites are in no way, shape, or form, a town square. They are privately-managed, there is no practical scarcity on how many video sites can exist, and if you don't like YouTube's policies, you and your viewers can easily go elsewhere. Indeed, platforms like BitChute exist in large part to host channels that YouTube has banned.
By moving away from YouTube, you'd obviously lose YouTube's viewers and advertisers, and that may make your video channel infeasible if you're running it for-profit. But them's the breaks -- you're not entitled to another company's audience.
I'm not saying that this is should be how it is, and you could make a strong argument that it shouldn't be this way, but I think it predates YouTube.