You used the words "ugly", I didn't.
And are not talking at all about what I'm talking = strawman.
Even before the whole conscious being comes to play, there is neuropsychology that comes into play. My best female friend is a PHD in this fascinating field so I know quite a lot about it.
If the person automatically sees the person as the sex they are not, how can it be seen as discriminatory unless what you do with it is discriminatory. This automated placing will be different from person to person obviously, some will really only on the clothes and basic presentation while many others brain is more finely tuned and will be able to see fine distinctions at the unconscious level. Once this automatic gendering was done, the brain will also automatically assign a whole slew of characteristic to that person, its a fact of neuropsychology (since my best female friend is a PHD in this field I know quite a bit about it).
So, even before the conscious mind comes into play, and a single word has been uttered, this is the state of the world.
So, now your asking a person to treat that TS as female even though the autonomous reaction ID'd the TS as male. That has to be done at the conscious level, which introduces a whole new variable into the mix.
Since many reactions to different genders are done without going through the filter of the conscious mind, going through it and possibly reevaluating gendering while talking to that person will skew their reactions to them away from the usual response.
The TS, may not know that the response is not the usual one, maybe everyone's they meet are respectful and that's enough for her; for many TS living in the real world, that's all they initially hope for (including me).
But, if the TS is ID's alternatively female and male, she will sense the difference. I did in the beginning. There is a subtle to not so subtle difference in how people react; though that doesn't mean the reaction when ID'd as male is bad, its just different.
If the person is never treated exactly as a GG because nobody id's them as such and there is a long standing atavic response to gender, should people flagelate themselves for "only" being respectful and while using the correct pronouns and the like, not giving them the full GG treatment when much of this happens at an unconscious level!!!!