Say FU to me in real life for rolling 8/9 evades, and see where that gets you. Anonymity can embolden some to say things they normally wouldn't.
I dunno, I'm pretty sure I've said that and worse to people I've played with. Of course I was grinning at the time, so they knew I wasn't saying it to be a jerk, saying it more as a joke.
Maybe the guy you played against meant it the same way but didn't realize how badly tone carries over text.