This is just factually incorrect. A simple google search for "reddit hate speech" limited to the last year brings up major articles on both maintstream news sites and smaller niche sites. Dozens and dozens of articles. Reddit has also been called out fairly regularly for their stances on pornography (allowing things like "r/jailbait" for years). They regularly do mass bans because of the press.

Reddit’s bias is aligned with the mainstream media’s, so they get a pass. The same is largely true for Twitter.

It gets brought up in a different context. Until recently, Reddit had no rules against hate speech, with the CEO explaining openly and at length why free speech principles speak against such rules and why the company won't institute them. So you could (and people did) write news articles about terrible things people say on Reddit, but you couldn't claim Reddit was being hypocritical or point to a policy they're not properly enforcing.

Now that Reddit does have a hate speech policy, I expect we'll start to see them in the same conversations.

I'm not sure if that's correct. I think r/The_Donald managed to keep Reddit in the headlines by itself when it still existed.

Because everyone has written it off as a lost cause.

Heck, "unsubscribe from all the default subs they're a cesspool" has been the going advice for at least a decade now. If that doesn't say lost cause I don't know what does.