In the past, there was just a bit of friction before filing a bug or dropping a comment on a project.
You had to sign up for bugzilla. You had to sign up for the mailing list. Something. Anything.
It was just enough friction that you had to want to post that comment or file that bug. You weren't going to waste your time just to be a shit.
With everything on Github, it's simply too easy to quickly slap a thoughtless comment on a project (guilty as charged--sadly).
I know that if I were releasing a project today, I would make sure to use anything other than Github.