Is blocking people on Facebook good?

Sure - especially if it is someone that you don’t even know in one of the groups you like and they’re always posting stupid content

I have “hidden” some of my friends even because I get tired of what they post. They don’t know I don’t see it - they might notice I never “like” or comment but oh well

If they are toxic and make your experience on Facebook unpleasant, then yes, I think it is a good feature. Just don't abuse it.