Parler asks for an absurd amount of PII. I always figured it was a way for the Mercer crowd to assemble a dossier on the extreme right for use in future highly targeted mobilization efforts.
The only time they request additional PII is for verification.
(As a security & privacy advocate with a job in the space, I dug into this last summer and again just before the January shutdown. It was never true just for signing up.)