CM
Adventurer
When people talk about chain mail bikinis, they aren't talking about literal bikinis made of chain mail. They're talking about gratuitous sexualization of female characters.
This may come as a surprise but it's not always male gamers who like sexy female characters. I've known quite a few women from my WoW days who transmogged to the sexiest armor or refused to play certain races based on their looks.
At least the male halfling and tiefling in your covers are also showing off equivalent amounts of flesh.
(edit): I agree, the PF sorceress is over-the-top, as well as the 4e warrior from the tiefling cover, but the others are hardly overtly sexual, unless you want to count the existence of breasts as sexualization.