The reason is because people use it for whatever agenda fits. It's a Rorschach.
Cons see these quotes and think it's applicable to "PC culture" and think George Carlin would tell kids to toughen up.
Libs see these quotes and think it's applicable to "truthiness" and the post-truth world the alt-right spins.
Truth is, George Carlin died in 2008. He missed the entire Obama years and the Trump era. We have no idea what he would've said or thought about the evolution of culture, of cancel culture, of Trump, of trans rights, on Ukraine.
Learn from the man what you want, but don't try to find quotes from 2001 and go "Hey wow look, it almost looks like he's talking about <blank>" here.