I've spent enough time on the backline as Bard and Machinist to notice a frankly staggering amount of DPS who either don't know how to work their Job properly, or straight-up don't give a damn. Up to and including some who don't even press buttons and just AA everything.

I've spent enough time on White Mage to notice a genuinely disturbing amount of DPS who didn't get the memo that Larryzaur makes memes and not actual 100% serious guides.

I've spent enough time on Paladin to have a feel for how fast certain pulls should, on average, take for a given party comp.

It's a matter of how the DPS of a run stack up against those baselines. If they're just alright, I might comm them depending on what the rest of the party was doing. But I like to imagine I know enough that I can spot the genuine gold-standard players who give it everything they've got and aren't just going through the motions, which I understand can be tempting during the long grind. If I see a DPS player working their ass off speed things up while properly handling mechanics, I'll usually toss my comm their way unless something crazy happened.