I'm not angry about any of this at all. I surely agree that speaking out of anger is a classic mistake. There is however no tone of voice in text and if you just speak an opinion that hits someone else's buttons, they're going to get angry no matter how much you insist that you're not speaking out of anger.

Here is the standard guide for offending people on the Internet:

Step #1: say anything at all, about anything.
Step #2: wait.

Thats really all it takes. :)