Yeah, definitely. I think it's arguable the same rational could even apply to a dating site for straight people. It would take a little more work and probably be less fruitful overall, but an adversary's intelligence agency could use it identify straight people (with security clearances) who may be trying to cheat on their spouses or whose marriage is disintegrating. Both of those situations could open someone up to manipulation (a honey trap [1], for instance).
Knowing someone is gay is a classic blackmail situation, particularly within the gov world. Grindr is very sexually charged, so you get the most extreme sensitive bits here, combined with high profile people that are closeted and don’t want this information leaked. Not the same situation.
[1] https://en.wikipedia.org/wiki/Recruitment_of_spies#Love,_hon...