I get the argument, but it seems like small beans in the grand scheme of things.
For instance, it costs 5X more for me to register a car in my state than it does to pay for Precheck. And the car registration does not involve any background check or in-person interview like Precheck does. And Precheck is simply a convenience, whereas being able to drive is a necessity. So the vehicle registration seems like it ought to be several orders of magnitude higher on the outrage scale than Precheck.
As for the classist aspect...it's the airport. They already divide people by class for everything else. This is not like Disney World where they are suddenly introducing a highly visible class system, where there wasn't one before. Airlines shove class stuff in your face the entire time. Even when you are flying economy class, they are finding new ways to stratify you.
Argument from relative privation is a logical fallacy.