Toxicity, racism and even disrespect is intolerable.
That being said, punishing people for a comment, a post or a match on third party websites or even a public server is harsh. Of course it depends what kind of comment it was, but up until a certain point, you gotta have a thicker skin.
It is 100% correct to keep your website clean in order to preserve the experience for other users. And yes, people who trashtalk in pubs tend to do that in lobbies as well. But myeehh...
That being said, TF2Center is a good website and a good service... it's what we as users make out of it that makes it cancer. If there are no decent games because gamers are just trolling, guess what: its not TF2Center's fault. MN as has a "distinct" character, his admins are a bit... antsy... when it comes to punishments, especially bans. But you know that and you can just not be an ass to people. Want to use his website? Fine... Don't want to use it? Your call. But don't complain about the system if you are one of the people disrespecting it.
Unpopular opinion.