I think what is particularly concerning about this, is that when someone like this talks about "sex offenders", they're typically conflating any crime of a sexual nature with a "child abuser".
Except, someone who has committed such a crime still has rights.
It is also a violation of the First Amendment. Also, whatever he is doing there doesn't seem effective (and the article admits as such). It seems to be pure grandstanding.
I think it is dangerous to have groups of people who can't advocate for themselves (also it creates problems in communicating with friends / family). That makes it very easy for the government to dehumanize a group, to remove the rights of a group, then to pivot to attack the rights of other groups.