YouTube has content guidelines... that doesn't mean they are obligated to enforce them, it only means they have easy reasons to moderate content where they feel like it. Their only real interest is profit, generally through showing you ads (by keeping you glued to the screen, sometimes by showing you controversial content) and by harvesting data. I'm not saying that's "right" in a moral or ethical way, it is simply the truth. If you recognize that, then it doesn't matter that they are recommending videos that ostensibly violate their own terms, and arguing otherwise seems to make you just willingly ignorant. YouTube has no incentive to incorporate "regrettability flags" into their algorithm, except to the degree that it serves them.
I'd go further to say that YouTube probably could do a better, more thorough job of cleansing content on their platform, without any additional cost. But having a certain amount of content that is controversial, which panders to a vocal minority, etc actually serves their platform. They use the 1st amendment sometimes to justify this, but they actually don't care one bit about any of that. All they care about is money, and at this scale the dynamics get kinda interesting.
But maybe your question was rhetorical and masked an overall point you are now trying to clarify. But I still don't understand the point your making!
Are you trying to absolve YouTube of any moral responsibility, while personifying with them with agency ("they have reasons", "they feel like it", "the degree that serves them", "they care") and granting them rights ("1st amendment")?
As for what really motivates corporations - I believe survival, not profit, is the essential goal. Profit is just one strategy - but another is not poisoning it's own environment.