This whole thing seems absolutely nuts.
https://www.google.com/search?q=tip+line+contact+form+-%22po...
It's not public. The site was soliciting PII "tips" about abortions. Ostensibly someone might tweet out their address, phone number, name, and having an illegal abortion, in which case it would be public. But in this case, the vast majority of tips aren't going to be public.
The difference with most OSINT stuff is that the information is public in some way or valuable to the public.
Categorically, the site would actually be violating many privacy laws in many states, including things like GDPR. It's definitely a cross-border legal minefield anyways, so it makes a lot of sense why it would be against the terms of service to operate a site specifically to test these boundaries. Sure, it may be a Texas law, but where are the servers? Where are the people submitting the information? Where are the people currently located with information being submitted about? Etc.
If the information collected is public, why is this a not equivalent to other politically motivated data collection? (Or, is the information collected not public?)
There are sites that collect, collate, cross reference and publish individuals' OSINT repeatedly on various political topics. (voting records, financial contributions, gun ownership, financials, etc.)