Blocking people

Why do some people think blocking others is childish? The button exists for a reason
That reason being, I don't wanna deal and fight with people that keep bitching and yelling for the most stupidest opinions, most of the times
Like, it gets to a point where certain someone keeps complaining without you saying anything back, and you're js tired of it, and u block them, as simple as that
Or, u js find them annoying
I mean, ig you could say that if someone does or says something bad, and instead of apologizing and holding themselves accountable, and they js block people, now that is childish, but I'm talking in like, oh I js find someone annoying and u block them
Or like an ex u don't wanna know anything abt, bc I've met people that say that blocking your exes is childish, like wha???