'Who cares about the marginal impact of an individual's actions?'
Someone who is trying to understand their motivation (what they're trying to do).
'it's both ridiculous and irrelevant to quibble over whether the profiteers are "trying to drive" the artificial scarcity to which they're contributing'
It's not irrelevant. I responded directly to a claim in the comment to which I replied. No tangent.
'I honestly don't even know what you're arguing about.'
I'm really interested to know why some folks (not you) are so insistent that the hoarders/profiteers are trying to create a situation (rig the game) rather than just being players in it. I thought the logic of my original point was pretty obvious and, as you say, it's not even that interesting compared with the wider point about the collective effects of the individual actions. So why are people so interested in this small point?