You do not have a fully defined view of sexism there. One other part of sexism is sexual objectification, which reduces the person or whole gender to an instrument of sexual pleasure, without any view of the person's dignity or humanity.
Objectification can be a component of sexism, but in and of itself is not sexist. It is a natural part of human existence demonstrated by both genders on a regular basis in a variety of ways. It is even the entire foundation of initial human attraction. It is not inherently wrong.
Men and women dance at strip clubs. They objectify the customers and the customers objectify the strippers. Hell, my butcher is an object that gives me steak for money and that is all we know of each other. That's okay. You are not obligated to regard everyone as a whole all the time.
We need to stop asserting that every interaction with each person (real or fictional, in person or entertainment) requires a holistic appreciation of every atom of their humanity.
If you objectify all human beings, you share a common trait of sociopaths. If the entirety of your view and interaction with the other gender is based on objectification, then you are probably sexist and have serious issues to deal with. If neither of these are the case, then you are probably a normal human being.
What fun would a pair of tits floating in the air be? I'd rather stare at tits that are attached to a whole woman.
And I said that nobody was reduced to being just a sexual object.
No, you're right - men who see just a pair of tits think "that's all I need - nothing attached, just the tits pleaze, tyvm."
More to the point: the women are being used in a way that is completely determined by the user of the app, instead of being given any kind of consideration as people.
If I am staring at a woman's tits - I am certainly giving her whole person my consideration, even though my eyes can only look at one thing at a time. WTF would I do with just a pair of tits?
No, the reason I'm looking is that I probably want more.
This app removes the women's ability to participate in the exchange at all. They have no control and are presented in a way that is completely in control of the user. When you remove her ability to decide how her body is being used, you are not considering her as a whole person. It's not about tits.