Was the tank in the OP a bit of a douche? Yes.

Did the tank in the OP have a point? Definitely.

Should the OP be using those parses as a means of improving themselves? Of course. OP seems to think their DPS is fine for full 340 in savage content.

It really isn't.

That said, if people didn't always generalize that people with parsers were automatically assholes then a big part of the issue here would disappear anyway.