Of all the things you could critique DSA on, this is the hill you're going to die on? 
DSA deciding to do a mask mandate at this event is unequivocally good and based. Shut the fuck up, you fucking dipshits.
Imagine being this much of a fucking goddamn crybaby about masking. Eat shit, you ableist fucks.
One of the biggest lessons this pandemic has taught me is the astounding number of people for whom leftism is really just performative, and that when push comes to shove, these people will make the biggest fucking stink about having to do something even mildly inconvenient for even a single fucking event or context and show themselves for who they really are.
For the same reason they threw a fit about seat belts and motorcycle helmets. Its a generic "You can't tell me what to do!" impulse that runs rampant among American libertarians.
It didn't stop with the libertarians.