Of course commenters can and do criticize any startup here, YC or no. Every regular HN reader knows that. You're not, however, allowed to derail discussion by inundating a thread with angry/obsessive posts and made-up sinister scenarios. That's what you've been doing in multiple threads now, including over 20 comments in this one. That's not curious conversation, which is what HN is supposed to be for.
We moderate HN threads less, not more, when YC or a YC startup is the topic (https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...). but 'less' does not mean we don't moderate at all. Until now we've moderated your comments much less than we would if you had been behaving this way about any other topic, but enough is enough.
Standard HN moderation practice, when users do this kind of thing, is to penalize and rate-limit their account. I'm going to do that now. (Edit: I changed my mind later. See the explanation below.) Since the reaction this will educe is predictable, I might as well answer it now: no, this has nothing to do with criticizing YC or YC startups. It's because you've been posting a plethora of low-quality off-topic comments and otherwise breaking the site guidelines. This is standard HN moderation and the only thing different in your case is how long we held off doing it.
Actually, IIRC, you're rather a good commenter apart from this, so if you want to fix this, it shouldn't be hard.
Edit:
For some reason I realized later that I didn't feel good about penalizing your account. It's not that what I said about standard moderation practice was wrong or anything—I just have a feeling that you're a good HN user coming from a good place and that there's probably a much better way to fix this. So I'm going to go with that instinct, and have removed the rate-limit etc.