Weird... I was kind of thinking the same thing. Call it a bit of bisexuality I guess, but I can't help but enjoy watching male or female strippers. I don't even want them on me. I just like to watch.
I don't know that it has anything to do with sexuality, but I suppose that depends on the individual. One can appreciate eye candy without finding it titillating.
There is nothing wrong with standing hip-cocked and girly. Some of us like standing that way.
For individuals (or NPCs) who choose that behavior, no - there's nothing wrong with it.
Forcing the PC to be girly is probably not a great idea, though. A character that sticks her hip out as shown in the poster - or walks/runs like Hawke or the Inquisitor - is not a character I want to play (or watch for the entirety of a game).
I'm completely with you in the belief that some things should develop within the lore.
I think the implementation and the treatment of how the Asari effect the galactic culture has always been a little inconsistent.
Between their cultural preference for mating with other species and their omnipresence as strippers/dancers, they were really set up as sex vendors to the galaxy - which can lead some observers to conclude that their primary source of power and influence is sex appeal. There were plenty of codex entries mentioning a strong economy, arts and culture, political prowess, and combat success - but all of that was later called into question by the revelation of the Prothean beacon and direct influence in their development.
I really don't understand what Bioware was trying to do with their portrayal - it is a mixed bag at best.