The main themes you want to touch
- Security: Need to protect everyone’s Private Identifying Information.
- Violation of Facebook policy: It is against Facebook’s user policy to share login information.
- OFCCP regulations against asking for marital status, children and age.
- Be polite but firmly say “no”.
You could say something like this:
“I take the security of Private Identifying Information (PII) very seriously. I protect everyone’s PII just as if it was my information. Therefore, I cannot compromise my PII just as I would not compromise anyone else’s PII. Plus, I do not want to violate Facebook’s user policy and have my professional account shutdown. I am sure you do not want to put your company in violation of OFCCP regulations against asking about marital status, children and age which would be compromised by my Facebook profile. I must respectfully decline.”
If you do not get the job, you may have a legal standing for discrimination.