Are Inactive Accounts Indefinitely Banned for Spam?

Had an account here that has been permanently banned for spam. It had a password manager generated password so quite strong and unique to this site and unlikely to have been compromised.

The only thing I can think is that the account may have been considered inactive (albeit by strict standards).

Anyone know if inactive accounts are permanently banned for spam? How long does the account have to be idle for to be considered inactive? Or do I need to be concerned about the password manager I'm using?