You're delusional if you think swapping the main character in a game like AC takes a day or two. Even if it was a simple copy and paste and the new skeleton is magically working out of the box for the thousands of animations in, that doesn't account for new facial animations (I mean, unless they want the woman to have the same build as Arno), reworking the microtransaction armor, a separate voice actor, etc...
It would've been great if the option was there, and I approve of games with those options, but the "game doesn't have X so the devs must be lazy" argument is ridiculously ignorant. I'm not concerned about the gender politics of this at all, but rather the demand for a standard in which the main character is always customizable - even where it may not fit - or else the devs deserve shit.