Ask HN: What's with the culture of suppression of dissenting views?

I've been on this site for over a decade, under different names. Generally I've found it to be one of the better tech-focused and smart online communities. However, I've recently caught myself self-censoring and avoiding sharing provocative or speculative opinions, since they immediately get downvoted (often without any explanation). It seems like there's now a culture of conformity that punishes for dissenting views. Is it (A) in my head, (B) an inevitable stage of all maturing communities, or (C) something else like the state of the world at large?