There's no magic AI in Grindr that can answer the question "Show me all people that work for DoD that are into gay sex". There has to be some engineer or group of engineers to do it. It is the same with a Hinge/OKC/Match/etc.
Because they don't have a bunch of location information for everyone on grindr?
If only someone did something in the last few years that would make this data super valuable. Like if Chinese intelligence broke into the US governments HR system and absconded with the data (including all their personal information including where they live).