internet communication seems to bring out the worst in people. Look at the things posted on this site, or read the comments section on twitter. I've seen people I know to have high moral character write things they would never dream of saying out of loud. When I was in college I wrote some stupid things in the comments section of an article. A few hours later I was mortified by what I wrote. I learned to be much more careful with online posting from that point on. It's way too easy to get emotional and write something you will later regret.
This isn't about the thought police, and it isn't about how "awful" these kids are either. It's a lesson on how easy it is to get carried away on the internet and write some really dumb stuff because you're trying to troll strangers or joke around with friends. One person says something shocking for a laugh, then the next person has to push it just a little further in order to keep up. Before you know it, everyone's way past the line of what constitutes acceptable humor.
I'm willing to bet a hefty sum that the in-person team culture wasn't anywhere near as bad as the emails.
If the coach was pushed out the back door over this, that seems extremely unfair.