In civilized times, shit could be anticipated and controlled. Shit had been colonized (hehe, colon). Nowadays the shit is fighting back and popping up when not expected, like diarrhea. "Shit's wild" means we're witnessing social diarrhea.

In reality, I say "shit's wild" so I don't have to voice actual opinions to normies, thus not making them uncomfortable. It's also a kind of shibboleth to see how woke they are.