The problem here is not some sort of scary foray into eugenics. The problem is that the app gives you essentially no information on who to date because genetic diseases are, thankfully, rather rare. “Come use our dating app so you can avoid dating a few people who you very likely weren’t going to ever date anyway” isn’t a particularly compelling sales ploy. The entire point of dating apps is to help you narrow down the bewildering array of potential choices to those who are (1) interested and (2) compatible in some way.

That is, the problem isn’t that the app calls up demons of past atrocities. The problem is that its key feature is useless for the domain in which it’s being proposed.