Will it stop these incessant virus PMers that seem to be trading and/or hacking forum accounts?
No. 2FA is useless against phishing sites.
For those phishing sites that are copy of this forum, that would be useful. Stolen passwords wouldn't be enough then, at least for people who enabled 2FA.
I meant against the phisher account buyers themselves. Wouldn't they have to get the 2FA secret keys from the people they buy accounts from?