I completely understand why you'd want to rage at someone doing 450k DPS in a +17-18, you're asking yourself "How did you get here?". It's a form of them not caring, people want to do the high keys and completely understand it, as did I, once, but limited myself to what I could do.
That doesn't give you way to say dumb shit, but if you do, I understand you perfectly and you're mostly right, regardless of what people say about it. Try not to go too hard.
Back-story: We had a mage pulling 900k in a DHT +17 (I was on 850k) and another mage, same ilvl and good legendaries, on 450k overall damage. You can tell the distaste we felt when we wiped right before Xavius because the tank couldn't wait a bit (Who the fuck still uses the invisibility potion thing on Tyrannical?), the higher mage went full berserk and while I understood him, don't say stuff like "I hope your family dies", what the hell?
I love me some literary killing of the other person (I mean, write some smart insults, without being a redneck), with juicy passive-aggressive lines, but wishing death upon others is...crazy.
Cool down, almost none of the higher mythic raiders are toxic and they got bragging rights for sure.