Strong disagree. I don't think the standards have changed, I think they have become obsolete. I personally believe the HN community have taken over the self-censorship role with the downvote mechanism, like a kind of digital Red Guard policing anything that smacks of wrongthink. It's a way of disappearing contrary opinions by abusing the moderation tools. I'm not arguing for parity. There really is no expectation that there would be political balance when the audience is global but the politics are heavily US-centric. But should people who think opposition voices are not to be platformed be given censorship powers? Please fix the downvote problem.
I don't believe that "shills" or "operatives" need necessarily be a large percentage of posters to influence the discourse towards their ends. If the overall discourse is already biased, then the role of operatives is simply to suppress dissent by demonstrating that some comments are simply to be dismissed and downvoted. This talk of "evidence" is outdated and will not fix this particular issue. HN has some kind of acquired autoimmune disease. Fix the downvote mechanism.
If dissent were allowed to survive the downvotes, then the risk is that the fence-sitters or those without political or other interests might see the "majority" view is a paper tiger. Some combination of true believers and bad faith actors can easily suppress other voices. The result is that heterodox opinions aren't allowed even to be read. Other voices are driven out. If it isn't fixed or if politics isn't banned outright, then HN will fade into a parody of discourse. I urge you to fix the downvote mechanism.
These rules about tone are all well and good when diversity of opinion is permitted. But understand that 99% of the time I am responding TO one commenter but AT another (potential) reader with a more open mind. Provocations and heretical opinions must be allowed in order to attract THAT reader's attention.
Many people can see the range of political opinion on HN is heavily skewed. If you want to argue your data says otherwise, your data or your method is flawed. Fix the downvotes, the rest will follow.