I’m part of the group that uses the first excuse mentioned in the OP, but that’s not the only reason. As brought up in said post, the male avatars are generally built like meat mountains (yes, there are exceptions, but they are exceptions for a reason) - which is fine if you’re making a meaty tank or warrior style, but looks plain dumb if you’re playing a caster or rogue class.
Especially wizards/priest roles, where you are constantly looking at what is effectively a linebacker in a robe or dress. My rule from WoW onwards was that if it was a cloth wearing class (which is generally in 90% robes), I was making it female. It is just much more pleasing in proportions. Since I find the healing classes to be more fun in group play than dps (and I hate tanking), about 80% of my avatars ended up female.
There is a converse as well, and EverQuest and WoW are just as responsible for it. If I was making the rare (for me) plate wearing class, it was always male. Because those two games (much less so these days but still) had a very, VERY bad tendency to make the same armour on a female into a literal ‘breastplate’ or bikini. It was plain dumb and sucked me right out of any immersion just as a linebacker in a dress did.