This is assuming things that are partisan one way are similar to things that are partisan in the other way and counter partisan content.
Avoid censorship, censorship is too easily abused.
Censorship in general is terrible, and abused very regularly. Even on the really small scale I see little mafias pop up all the time, such as on forums, where anyone a bit critical of the select group gets banned and their posts deleted. On a larger scale is Putin announcing that criticism of the state is to be censored, citing other European laws do just that and punish people for what they say. If someone is censoring someone it is just extremely suspicious, and I don't blame anyone for going 'it is censored, therefor it is likely true', because the censor has removed the information that could be used as evidence for whatever it is.
"When you tear out a man's tongue, you are not proving him a liar, you're only telling the world that you fear what he might say." - George R.R. Martin, A Clash of Kings
Moreover, we're talking about the recommendation algorithm. The only neutral recommendation algorithm is a random number generator. Everything else is making a decision that video X is "better" than video Y for user Z. What it means to be "better" is difficult to analyse, but Google themselves must be constantly reviewing that question.