As with any social app, banning sites/users/apps that aren't deliberately damaging (like spam, trolls, whatever) is basically saying your system isn't working,

As with any social app, banning sites/users/apps that aren't deliberately damaging (like spam, trolls, whatever) is basically saying your system isn't working, and you can't be bothered to change it. It's like 'fixing' a bug in software by simply suppressing the error messages. It will come back to bite you in the ass.