No idea. I get random emails from shady "meetups" and networking events too. I can't report the spam and unsub fast enough.
The recruiter spam has transcended LinkedIn too. It's mostly direct emails from recruiters. I wouldn't mind if the jobs were even slightly related to what I do. It's pretty clear I'm a designer and frontend dev, but I get spam for Java and PHP gigs all the time...
I have the same thing going on.