I was interested to see what you had put here under Comment Policy. I totally agree. I have no problem with someone disagreeing with me, but it doesn’t have to get nasty. I had someone comment on one of my posts a while back. This person did not follow my blog and had never commented before, but now did so in a manner I found rather rude, so I deleted the comment. Then they commented again quite nastily. This one I ignored. It takes all sorts I suppose, but really, if you don’t like something, don’t read it!
Yes, it happens from time to time. Some people just want to have an argument which is very different to having a conversation with differing views. You can put people’s usernames and email addresses in the comment blacklist at Settings > Discussion to block specific users from commenting on your site if you get any troublesome ones.