Sadly there are lots of reasonable-seeming right-leaning people whose discourse about 'real issues' sooner or later circles around to 'race realism' or 'the jewish question' or some other ideological Pandora's box. It's often later; a common rule of thumb among far-right extremists is that it takes at least 2 years to reliably indoctrinate a person online.
Here is an example of how these persuasion techniques are deployed, albeit a slightly offensive one. This particular example (spread across 3 pages) aims toward recruitment of people for the 'Qanon' conspiracy which is popular among some right-leaning people. While it's orthogonal to other far-right extremist movements, it is a useful example of a developing militant ideology.
https://centipedenation.com/library/red-pilling-a-general-gu...
I think an equally large problem is reasonable-seeming left-leaning people who hold some opinions so spectacularly absurd in the name of ideology that it generates very fertile ground for right wing commentary to resonate.
Some peoples actions are excused and excused and explained, others are not.
Regarding debate or YC or socialism: unless people get abusive I find it hard to believe that it would be called toxic. If you could link to it or provide an except of content that would be called 'toxic' without that content being 'abusive' that would be helpful.
When I complained about his moderation by saying this:
>A moderator just a hair left of your current moderation approach on the authoritarianism scale would "flag and remove" PG's entire recent article about income inequality with a note calling it "tedious ideological posturing."
For that comment, my entire six-year account was banned and I was told to email ycombinator to have it restored.
When I emailed to have my account restored, I was told this:
>We're happy to unban accounts when people give us reason to believe that they won't repeat the things that led us to ban them. In your case it's a little less clear what that reason might be, since you've expressed how much you dislike a bunch of things about HN, our moderation, and me. But if there's something we could do to help you have a change of heart about those things, let me know.
So basically, since I complained about his moderation, he took it personally, and only if I was willing to revoke my criticism of his moderation could I be unbanned..? I was never able to get clarification on what exactly needed to happen for me to get unbanned. The gist was, if you argue consistently in favor of free-market approaches to anything economic, you will be accused of "tedious idealogical flamebait" and eventually be banned.
Take it for what it's worth, but I was never what you would call toxic by any standard definition, and those were my results.
The reason why YC seems more left-leaning nowadays compared to a few years ago, is exactly what the grandparent of this thread suggested, anyone right-leaning (or libertarian) has been harassed off the site / strongly discouraged from sharing their perspectives.