That's quite a claim when, until Grindr's practice of selling PII was disclosed, no one had any reason to imagine that by using the app they would be disclosing their sexual orientation and behavior. In light of that I have no idea what preference you imagine to have been meaningfully revealed here.
My claim is that for a large number of Americans, it's probably worse to be outed for seeking extra-relationship (I'm not sure of the proper term) casual sex than for being gay/bi/queer. Of course, both of those could be revealed at the same time which would be quite the double-whammy to an unsuspecting partner.
I'm not sure I agree, though. In an open relationship it'd be no surprise to my partner if I were using Grindr (he probably would be too, in that case!) and I think therefore that'd be more or less orthogonal to the concern around the risk of forcible outing posed by Grindr's misuse of data. Both are certainly of concern, but I think independently so.