[wakawaka28]

This might be a way to protect people who really don't want an account from having their identity stolen. If you deleted your account, one of your connections could see that and make another one in your name to mess you up.

[iszomer]

Akin to FOMO? Some services will retain your used account usernames post-deletion while others do not. IIRC, facebook does the former.

[wakawaka28]

I don't know what you mean. People are saying that Facebook wouldn't allow them to reuse their own old username. I think it's to prevent identity theft as someone could pick up any deleted username and pretend to be the old owner. They could even re-add the old owner's old connections to establish the scam. A few people might think "I thought I was already connected to this guy!" but most wouldn't think twice if they saw that the username and photo were the same.

I think it makes sense to allow reuse of usernames, but only after a sufficiently long period of time. I don't know if 20 years is enough, but something in that ballpark would be needed to reduce the risk of identity theft.