Anyone can copy the first and last name of anyone posting here, and send an email with that as the display name. (and the real email is say anayon23@g-mail.ru) .

The person who gets the email sees the first and last name of the person they know.

How does certificate security stop scammers impersonating people on email? Unless the site also requires everyone to create an account and create a username that is not their real name. And demands that communication is only ever done within the platform like your site or PCF.