Sure sometimes is difficult to discern whether a post was an actual threat or just figurative language, but is it really that terrible to delete a post that was calling to shoot people even when maybe the intention was "just figurative"?
But to your comment, which I think I can respond to: if I perform illegal activities on a platform, I don't think there's really a choice at that point as to whether the platform can take it down. Death threats, posting child pornography, infringing upon copyright…all of those are things you can go to jail for anyways, so it's not really a "free speech online" issue at that point.