Some services give discounts to students without removing any features. Is that bad, since all the other customers are getting the same service but have to pay more for it?
Nope. I don't have an issue with price discrimination if those being favored are given a price bellow the baseline that everyone else gets. That is not what's happening here. Tinder is charging certain people more than other for no reason other than who they are.
If Tinder wants to overcharge certain demographics, they have to do it to the majority or offer something of equivalent value to them in return.
To play the devil's advocate, could you not argue that this is more equitable? People of greater means pay more for the service, and keep the lights on for the less fortunate who still get to enjoy a well-funded product?