Hm, for some reason I thought there was a question box for this topic... if there is, I apologize for missing it! I wanted to add my two cents on the topic of what and what not to call trans people, specifically the "MTF" and "FTM" terms.

Now I will own up to the fact that I am not a trans person, nor have I ever personally known a trans person, so I'm the last person who would have any sort of say in the matter. But I do have an opinion from the perspective of the type of person who is likely to use these terms applying to any trans person ignorantly, but innocently.

Disclaimers out of the way, here are my thoughts:
You have said that MTF and FTM can be insulting because they ungender trans men and women and place undue emphasis on a gender that they may not associate with at all. However, to me it seems someone would specify FTM and such because, regardless whether or not a person associates with their physically born sex, it does play a huge factor in how that person has lived, what they have gone through/will go through. Context aside, I don't really believe that people deserve to be scolded for using the term when perhaps the emphasis is meant for the trials and life experience that trans persons go through, not the sole fact that they were born a certain way. It's not meant to ungender someone, but to identify that this is a person who has gone through a lot mentally and perhaps physically.

It's not meant as an excuse. After reading what you have written I much prefer trans man and woman to the acronyms. At the same time, I still do not see the harm in using them and wouldn't fault someone for it unless the rest of their speech is overtly ignorant or insulting (the likes of which you have called out, and which I applaud you for doing).

I have to say, this blog causes a lot of mixed emotions in me, but I can't deny the discussion it sparks is very interesting and often insightful.