The argument against that is that if sellers cannot increase prices in times of crisis they have no incentive to stockpile for such events. This leads to shortages and even higher prices on an unregulated black-market.
I'm not saying that I buy this line of reasoning, but there's the counter-argument.
It's not really an applicable argument here. That's a general time/availability/word situation discrimination, which I think I would be ok with, to a limited degree.
I was arguing against people based discrimination, without any meaningful relevance on availability. Again, I think reasonable and reasonably qualified discounts are ok, but not increasing prices for the same product and service.
I'm not saying that I buy this line of reasoning, but there's the counter-argument.