How does Apple restrict you to a single Apple ID?

I use my personal Apple ID for personal things, my work one for work things, and as an admin of our Apple Business Manager account I can create new Apple IDs for anyone in the company as necessary.

To my knowledge Apple doesn't even have a policy of requiring one account, I've certainly been told to set up separate accounts by Apple support teams.

Facebook does have this problem, they have a policy that you must not have separate IDs, they police this heavily with a lot of automated bans, and they also require a Facebook account to do development with Facebook.