It is so simple that it is laughable.
Create your ‘official’ email only used for ‘official’ business. Create your ‘friends/family’ email for just friends and family.
Join sites using some invented name with some other email.
Mask your identity.
If you do it right, no one knows if you are a man or a woman, if you live in the U.S. or Estonia, if you are 21 or 71.
Think of it; how would anyone know anything about you? Your ‘official’ email doesn’t link to anything, nor does your family/friend email.
Your Facebook account is under a nick with a crapmail account.
Nothing links that crapmail account to you.