I know a lot of people are upset about resellers, but even though I do not partake in this practice, I see nothing wrong with it. Apple sells a product for a particular price. If someone wants to buy it for that price then fine...and it is up to them to decide what they want to do with that phone. It is not our place to judge.
As an example, would you be upset if someone bought the phone and then sold it for $100 less than what they paid for it? If not, then why would you be upset if they paid full price for it and then sold it for $100 more? I’m just illustrating this as an example.
They can use it, they can sell it, they can even blend it. It is their property and they can do as they see fit.