While I appreciate what they did on one level as I think it will help the country better understand the sickness going on here it also sure sounds like a crime to me, so probably best to stay away.
There are two things floating around about this and only one is verified AFAIK.
A) Security Researcher Copied all the publicly available posts on the public web interface using a normal user account. It would be like if I web crawled this forum and copied all the message that anyone here can read. No crime in that.
B) Real hacker compromised everything hacked in and setup Admin accounts, has all the ID verification of every poster, including drivers license, and social security they used to verify themselves, all the private communications, and deleted messages.
A) is verified to happen, and is not a crime. Still juicy info, but no primate messages, and no drivers licenses.
B) is not verified, and would be a crime. This one may be trolling the Parler users to make them nervous about what they posted.