Rather, I think they're trying to profit from an asymmetry that they believe exists: that there is a significant population of people over 28 who would really like to hook up with people under 28, and are willing to pay for the privilege.
They may also believe that they will be more attractive to their core demographic if there are fewer older people in their system.
They may even believe that they will be more attractive to their core demographic if their older demographic skews richer.
No idea whether they're right, but they presumably have a pretty good data-set to work from.
It gives you undo, which is a minor advantage, and it gives you passport which can be accomplished for free on any unrooted Android phone or any jailbroken IPhone.
In the future it will prevent you from needed to see ads, but I imagine that will also be a minor advantage.
Marginal use of Tinder probably decreases among people who feel excluded by the price discrimination and do not buy into it.
Marginal utility of Tinder probably increases for the college-aged target demographic if marginal use of Tinder by older (especially poorer and older) users declines.
At least, that's what I think Tinder is hoping will happen.
But in any event, even if they were going to move into "social discovery of anything" as a technology company, it does not follow that the current Tindr app and accounts is going to be used for "social discovery of anything," because it is obviously absurd to imagine that people want to use a hook-up app for "social discovery of anything." There is no market for people who are like, "Hey, I want to find the perfect drapes for my living room remodel and also at the same time look for casual sex."
In this case tinder is not charging unnattractive people more. Tinder has an algorithm that shows (mostly) only attractive people to other attractive people. That part is free!
That said, I don't agree with this pricing strategy.
I agree that age is probably a good indicator on that. I still think any tech associated company that brings in age is just asking for trouble.