I had a similar experience with Facebook, although my email was much more aggressive (this was when their recruiter contacted me right after I got tripped by one of their UX dark patterns in a way that translated to real world harm). I kept getting invites until I put a clear statement expressing my desire to never ever work for Facebook into my LinkedIn profile

FWIW I think it's because recruiters at most companies are effectively contractors and don't have access to all history of communications.