On the surface, the scalper helps you grab something, but in fact, the scalper grabs something that originally belonged to you. Why is there this misunderstanding?

You are right, it should have been yours originally, but it is not certain, or it may take a long time to get it. Scalpers use some illegal means to confirm this possibility, or save you a lot of time. Objectively speaking, it destroys social fairness and wastes social resources, so it must be severely cracked down.