It also has minimal upside because YouTube makes more money on high view count videos by far, so removing only when a certain level of fame has hit a video cuts off the part that is economically interesting to YouTube. The tail is a loss leader.
Your scenario is not very plausible to me.
By all account YouTube are arbitrary with bans and blockings. That's not the same as unlenient.
The standard example of the phenomenon I'm describing is from Twitter. They successfully keep nazi content out of German twitter, but not the rest of the world. That suggests that Twitter's moderation is partially constrained by their own policies, not just technical ability. I don't think this is a far fetched understanding of how any social network works.