That's only true if there is a downvote threshold that automatically hides downvoted comments, which I don't think Lemmy has implemented. I agree that downvoting can be used to censor and avoid discussion, but the justification for removing downvotes on Beehaw is something like "keeping a positive environment with no negativity from disliking" rather than making sure users have to voice their disagreements and not just smash the blue red arrow like cowards.

There are issues with both sides of the down button debate, but I'm more for it than against.

For a different take on the downvote button, yesterday I put a post up on a technical thread. I hadn't really read properly what the discussion was about, so my post wasn't really helpful even if well intentioned. I only noticed when I got a couple of downvotes. I looked again at my post, then at the OP, then realised my error. Eventually I deleted my post. So, in that instance, I found the downvote helpful to myself as well as for the rest of the thread: make sure I read the OP carefully. ;-)