That's a huge misreading. Hiding comments in the UI empirically does not suppress discussion, if anything it actually attracts engagement. Lots of people are seeking the "wrong" to "correct" it.
replySuppressed debate is almost universally due to biased/captured moderation teams aggressively using bans.
You're wrong, because if your karma fall below a certain number, your comments wont show up anymore. I can show you if you like.
replyPeople shouldn't be blocked from commenting because their karma goes negative. Spamming, hateful talk, etc should be a completely different system. Just because what you say is unpopular (in one place mind you) doesn't mean your words should be hidden.