I read it to mean “allowing unrestricted comments on a web page is a bad idea”

Perhaps you read it as “allowing unrestricted comments on a web page _or anywhere else_ is a bad idea”

But that second one has never been the case. People have alway been able to post responses on their own sites with links to the original. Many places like reddit are primarily that.

I think others maybe confusing the right to free speech with a right to vandalize.