A lot of the information a user who owns an account can see is not visible to the public. I don't see why being on Grindr in 2020 would be a blackmail risk IN COUNTRIES WHERE BEING GAY IS LEGAL.
OK, but in that case you're at (potentially much) greater risk than blackmail.
Why is blackmail the risk that people on this page are going to, then, is my question. If you're willing to make a public statement then blackmail is lower risk, not higher risk.
I'm not sure, sorry. I'm not honestly sure why there's so much discussion about security clearances.
If someone gets your grindr account they can get your (a) address, (b) phone number, and (c) private photos, none of which would otherwise be public. So let's just get that out there. A reasonable user would not expect that any of those three things are readily available to a stranger that they've never talked to who merely has their email address. Especially if they turn off distances specifically to avoid triangulation attacks on their location.
Those pieces of information can be used together to harrass, commit violence, or threaten to leak your photos or personal (albeit sure, not "private") conversations. Those are the obvious ones, but other information in there can also hidden from public view, like HIV status.
With this bug a malicious person could knowingly target you based on email address instead of finding you and even putting the work into catfishing you into sending them embarrassing photos.
I'd say that's a higher blackmail risk but only because of the hack, a little. Catfishes still existed but this makes doing it invisible and massive in scale while associating it with a public ID like your email address.
If you are visible on Grindr, you have made a kind of public testimony.
So, you have reduced your blackmail risk - since you're already at least somewhat prepared for this information to be public.