I don’t think that site would be problematic. After all, we’re just talking about custom interfaces to analyze public data.
A big part of the solution is that users should have an awareness that their activity is public. Every once in a while someone gets burned not knowing that anyone can view what a specific Twitter user or Instagram user liked (like politicians liking risque thirst trap photos).
Another is easy alts and throwaways, with tips to avoid correlations:
Don’t use the same verified email address
Don’t reuse usernames, including across platforms
Try not to use the same instances, such that instance admins can see whether login activity is coming from the same place, unless you absolutely trust that the admins won’t analyze your data OR inadvertently leak their records.
Be aware of the techniques used to correlate users: analysis of timestamps, linguistic/grammatical quirks, etc.
This is a public place, so people should be aware that this is a public place. That means they can still find this useful space, as with many other public places, but should be aware that the more they do on this platform, the easier it is to correlate with a real life identity.