I don't over think anything that is not required to be over thunk.
The ONLY reason ladies don't pee standing is they lack the choice.
When I need to pee the ONLY thing on my mind, is emptying my bladder and making it so I DON'T need to pee.
If I am wearing as usual a shirt and nothing else, I like that I can walk into the bath room and go without a need to do anything other than stand there and pee.
In public I am just interested in peeing and leaving. And it is both easier to just use the penis I am stuck with and go the easy way and not agonize over it. Granted, if I am wearing a dress, I am likely going to use the ladies room and sit. But then again, I might also use the men's room and hike the dress up pull the thing out of panties and use the urinal. Because easy is better.
And like as has been mentioned, public toilets are not always clean enough.
And let's face it, if you are wearing a nice dress, and you can pee standing and NOT risk it being stained, then defiantly sitting might be just that, a pointless act of defiance.
Peeing sitting will not make me feel more the woman.