Actually, I think "charging users to connect" is the only way to make an ethical dating app. The key thing is, everyone pays the same amount, and gets the same abilities within the platform. No freemium, no free riders. Everyone helps keep the platform sustainable.
You do still have to deal with the perverse incentive to keep people on the platform, but I have an even crazier idea for that: one-time single payment. Now the platform is incentivized to get people off the platform while still being satisfied enough to recommend it to incoming users. I suspect that could go badly in different ways, and might not be necessary if it's generally acting in the users' favor (possibly because of my craziest idea, having it be user-owned). I'm still thinking about it.
That or someone needs to run it as a charity. I'm not sure if that's more or less crazyb than the previous ideas.