Ah but... Does Sera personally think that all these things are shameful, or does she simply know that they consider them shameful and hence they could be used against them as part of the grand game? Can you truly judge that from one comment?
Yeah, I'm sure that pairing being trans with beating a squire (which rather isn't considered shameful by the nobleman who does it) wasn't meant at all to be shaming for being trans (or crossdresser as someone in attempt to justify Sera here mentioned as possibility - because apparently when you're a crossdresser, you deserve the shaming).
I'm not trans, but the amount of dismiss and denial reminds me a lot conversations I had with fans of shows that introduced "lesbian sleeping with a man and enjoying it" trope. Even the arguments are the same, including "People try awfully hard to be offended" and stating that by making any complaint they'll make themselves unlikable.
I don't have too much problem with the character herself, but with the writing - it's as if they intentionally made her unlikable (that was even what the devs said before release - that she's "love or hate" character, and they were right, she's the most hated character and they foreseen that, so they gave an option to kick her out at any time - and only her). Those little details that make her look like a close minded bigot don't seem so 'accidental'.
This is really problematic considering that lesbian representation in DA games so far was "A Paragon Of Her Kind" - story of psycho lesbian who betrays her female lover to gain power, leaving her for Darkspawn to turn her into Broodmother, by process that sounded like repetitive rape.