Quickpost and apologies for possible bluntness.
Thats how I perceive it, at least, taking into account what the only 3 transwomen I know tell me. One of them tells me that she's afraid of dating now because her previous relationships were all guys who thought of them as a cheap porn actress of some sort, who thought she should be thankful they're calling her with female pronouns.
I'd like you to support her and counter her fear; teach her, as that fear will only be detrimental in her life.
While misconceptions and misunderstandings may be in play (and the 'thankful' part may be more innocuous than what happens), genuine and sincere gratefulness is not based on a degree or level of expectancy in this context. It comes off as shallow, and superficial in the essence of thankfulness, if the last sentence is directly related here.
Which is pretty illogical in the first place if people knew what they were talking about. And...saying 'be thankful I'm calling you by your pronoun' doesn't really denote a good relationship if the tone is limiting 'you'. :/
Meaning: Help her with her fear, and educate others on this. No research supports that gender identity is directly connected to...err, those things mentioned [ie degree of submissiveness or 'receiving abuse'].
Its a bad thing when assumptions are taken as conclusions--specifically stereotypical ones. The realistic account is much more broad and brighter than what you present here though, and that's a great ray of hope (...meaning that stereotypes are really confining to thoughts, and make things seem so much more constricting than they really are.)
Though its sad that the initial experiences are negative.
Those play a role in future interactions due to memory.