Every passionate ideologue thinks that both the community and the moderators are biased in favor of their opponents. Your counterparts are just as certain that it's all biased in favor of you:

Typical modern leftist ideology. Very disappointed with HN lately. https://news.ycombinator.com/item?id=25955953

Hacker News has a progressive Silicon Valley bias https://news.ycombinator.com/item?id=26402235

this site is heavily biased towards the left https://news.ycombinator.com/item?id=26610757

the status quo here is California liberalism https://news.ycombinator.com/item?id=26719247

HN, where the SV/SJW group think prevail https://news.ycombinator.com/item?id=26731079

a mod who curates comments based on what's politically expedient according to leftist valley dweebs https://news.ycombinator.com/item?id=26866955

Ssshh.. You can't say that on HN. You might anger the WOKE mob! https://news.ycombinator.com/item?id=27227591

HN is best thought of as a machine for deepening the delusions of the left https://news.ycombinator.com/item?id=27242324

pure commie propaganda https://news.ycombinator.com/item?id=27269114

Democrat cultists https://news.ycombinator.com/item?id=27308327

HN is very, very authoritarian left https://news.ycombinator.com/item?id=27507112

90% of the HN audience supports communism https://news.ycombinator.com/item?id=27816841

HN is populated by the very liberal types https://news.ycombinator.com/item?id=27939890

this website (like most of the internet), is controlled by the far left https://news.ycombinator.com/item?id=28037354

This site is sadly run by militant commies https://news.ycombinator.com/user?id=k33n

This site is ran by the most radical socialist lefties San Francisco has to offer https://news.ycombinator.com/item?id=28203889

all non-leftie viewpoints are banned here https://news.ycombinator.com/item?id=28237072

HN moderation got outsourced to affiliates of the Democratic Party https://news.ycombinator.com/item?id=28291108

a total invasion of commies to HN over the past decade https://news.ycombinator.com/item?id=28065194

blue for how liberal it is [...] red for how commie it is https://news.ycombinator.com/item?id=29022117

insane how hard-left this forum has gotten https://news.ycombinator.com/item?id=29100962

HN doesn't like it when you criticize the US left https://news.ycombinator.com/item?id=29176196

That's a small sample, and of course there is an equivalent list of complaints saying the opposite. They can't all be right, and I don't think the odds are very high that yours are right while theirs are wrong (or vice versa)—the comments are too isomporphic and the logic too identical. Rather, some deeper mechanism is generating them, one that you/they have in common. What might that be? Well, there's one variable that has complete predictive power here: the ideological passions of the observer. Since the entire phenomenon is predictable from that, I assume it's being generated by it.

Moderation is far from perfect - for one thing, there's far too much content for us to see it all, and for another we make mistakes. But that's a far cry from "breeding a community full of extreme opinions, generally $ideology" and all the rest of it. Note that the one thing such complaints never come with is specific examples of all these horrendous things that moderators do or don't do.