What that writer is saying doesn't match what they are going on in their settings since 4e.
Bane came back pre-Spellplague, took back all his followers and power and then even added on top of it by conquering the goblinoids pantheon.
Myrkul is a minor god serving Kelemvor now.
Bhaal came back and reclaimed the murder domain from Cyric (who was trapped for 1000 years as punishment for the Spellplague) effectively making him a good again. This was mentioned in the Sword Coast Adventure supplement for 5e.
