This happened twice, in two different communities now.
The attached here screenshot shows 3 comments deleted for posting an opposing viewpoints, none of which have any insults. I was told my comment (and apparent ban) was due to violation of rule 1 - don't be a jerk. My comment had no insults or name-calling, only stating what I believe, and this result in a removal and ban without any further conversation. EDIT: to point out this first instance occurred within the Ask Lemmy community, and another person noticed this and posted about it - if it doesn't get removed it's here: https://lemmy.world/comment/7831856
The second time it happened (I will post links and screenshot in comment), I did not realize until today. Someone replied to my comment, and I tried to reply back, but could not - then went to check my original comment, which was removed, and I had been apparently banned - both the removal and ban were without any notice given to me either.
While clearly people disagree with my opinions above, I do not believe there was cause for removal and banning in either case. Both these actions are more indicative of attempts to outright remove certain viewpoints than to promote respectful discussion.