There are legal protections on products like generators and water.
Scalpers on consumer goods are just providing a market correction; rather than having the goods go to the lucky few to find the product on store shelves the product goes to the highest bidder which in theory who deriving the most benefit. The alternative is the only way to get a GPU/Console would be to wait in line the longest which would make GPUs unavailable for people who need them for work, research, etc.
It's not like scalpers have a monopoly on the GPUs, they are competing with each other while incurring their own marginal costs so it is unlikely that the scalpers would be capable of raising the price above the 'real' market price.
The GPU market is the prefect example since all the evidence suggests that the GPU AIBs and distributors are inflating the prices far before scalpers buy the cards. You can tell this is the case because the only models widely available are the higher-tier SKUs of each card type.
You can argue that a market in which there are scalpers is ripe for corruption, collusion, etc. but those are separate issues.
Right, because scalping totally only ever happens with videogames, and never with generators, toilet paper, and water.