You can choose to make your email on your profile public. Take a look at the number of emails exposed vs. the number of phone numbers exposed, there's a reason why it's a small portion, most people don't make that public.

This was just an attacker abusing "Who can look you up using the phone number you provided?" for users where this was set to the default of "Everyone" and then scraping the public details for the profile that popped up.