You're right that YouTube is not obligated by law to recommend videos. They do however follow their internal guidelines, which try to keep the platform open to ideas. Some of those ideas are distasteful to the majority of the employees at YouTube, however they will still in general respect people's rights to present those ideas.

Allowing monetization (where much of YouTube's controversies have been) is a completely different story since it also involves the demands of advertisers. The advertisers do have a right to avoid paying money to extremist content, just like you have a right not to donate to causes you don't believe in.

> first, do no harm

Easier said than done.

Challenge one is to define "harm" without classifying all sorts of alternative political ideas as "harmful".

Challenge two is once you've defined "harm", build a system that works at YouTube scale that can actually filter it. Also consider that it's a moving target - people are able to figure out how to get around YouTube's filtering algorithm, so YouTube needs to constantly update it to keep ahead of these people.