Yes, they already have it, and that is the concern. If someone in Chinese intelligence wanted high quality extortion material, Chinese ownership of Grindr means they could probably get it with relative ease.
I think what they're saying is that the horses are out of the barn now, reversing the sale won't undo the damage.
And now you just know that they're going to make some "offline backups" before the company changes hands. It's not likely that Grindr has bank-level auditing of whether a single bribed/coerced employee plugs in a flash drive.
Not sure how making it even easier to get this information is helpful or warranted.
Not every closeted gay man who will sign up for Grindr has already signed up.
Presumably Grindr is going to continue to exist and gain new users, possibly for quite a long time. Just because they already have data on 27 million doesn't mean we should just shrug and leave it open for future millions more.