Scalping exists when there is a discrepancy between a marked price and the market price of an item. If scalpers were not a thing, you would have shortages. With scalpers, you still have shortages, but you can acquire the good by paying a higher, market clearing price.
That higher price either makes it so that rich people can get the thing (most don't like this), or that people who really need it can get it (i.e. lifesaving medication etc). So your view of scalpers might be influenced by the distribution of (1) and (2) going on.
And yes they can suck up profits, that’s their whole thing. Are you saying that profits can’t exist in a functioning market?
The ant planned ahead for the winter, the grasshopper didn’t, and the scalper provides a service to the grasshopper, for a price.