It’s a form of dark meta-humor — a self-aware joke that surfaces an underlying anxiety (about violence or predation in dating), which most people suppress. The humor lies in making that tension — a latent fear — explicit, while ironically highlighting the absurdity of real-world risks that still don’t deter people from dating apps.
The odds of woman murdered from the initial encounter from online dating is very very low. There’s a 25x more likelihood of that woman being murdered is in a relationship already established since online dating. Nevertheless it is a real concern, and a schoolmate of mine unfortunately was one of those statistic from an initial encounter. So the joke albeit intentionally dark is not funny to me either.