Some people do take this game way too seriously despite not being in a tournament and get super worked up about it
But hey, it's the internet, what can you do
Fortunately, this unnamed person is not representative of our entire playerbase. Block 'em (left click on their name->mute/block player), enjoy the blessed silence, and keep them the block list as a reminder to NOT play with that guy ever again.
The opposite also holds true: every time you play a match with people you like, put them on your friends list!
(Obviously I do not know all the details, but in the future try discussing your strategy with your teammate in the lobby and see if he wants to roll with it, if not just try your best, or change your ship build.)