Yes. You have to install Greasemonkey or Tampermonkey and edit the script for boingboing, but it works like a charm to hide the users who add no value to the site for you (currently a mere five for me, three of them left-wingers)
You’ll also want to mute notifications about their comments in your account settings.
Apparently the Discourse devs are considering integrating similar functionality as a server-side feature. I hope it has back-end analytics to help the mods.
[apologies for the brief off-topic aside]