I hadn't actually realised that was the etymology! Last semester I taught a freshman comp class framed around black social movements and we spent a lot of time talking about the difference between liberal and radical political goals -- if I ever do it again, that will be a useful mnemonic for my students.

Teaching that class gave me a great object lesson in valorising definitions -- when I asked my students if they could give me an example of a radical political group or organization, the first response was the Klan...!