Earlier quoted context omitted.
It absolutely is evil. Buying out local inventory and selling it for a profit to the same people who would have bought it anyway isn't doing anyone a service. It's not "adding liquidity" to the market. It's not bringing more supply. It's adding a pointless middleman to a transaction that would have happened anyway - it's an inefficiency. It would be a different matter if these people were actually sourcing masks from…
I would perhaps grant you "evil", but "bad", definitely not. This is one of those rare things economists seem to agree on. [0] The scenario you described would be unlikely if price gouging was legal/encouraged as the extra profit would largely be captured higher up in the chain (e.g. by the production factories). This would incentivize the re-purposing of factories to manufacture the high demand products, discourage…
If you can legally sell your masks in time of crisis for a hundred dollar a piece, that's a great incentive to keep some spare capacity around that doesn't rely on global supply chains. Price controls dull the edge of that incentive.
(If more people were allowed to raise prices and thus kept spare capacity around, prices wouldn't rise so much in the first place.)