I never heard of BC.game deactivating accounts for inactivity.
I don't think it has anything to do about whether the account has 2fa enabled or not.
If there was such a policy, I would've read about it from here.
I've also not faced any type of account deactivation on any of the casinos however in past when I was learning Binary options trading, I had an account on a broker site, it didn't allow me to withdraw the funds so I left the account for sometime. After 2 years when I tried to login on the site, my account was deleted from the site and when I contacted their support team, they said that they deactivate and delete the accounts that are inactive for more than 6 months.