You are just assuming, that MS actually knows and cares for what users want. In my experience its the other way round. MS will introduce a change/new behavior and user have to adjust their own behavior, because most are not willing to switch to a competitor program.
I remember very well how much my father sweared at the computer because MS changed the UI to the ribbon bar. It wasn’t at all what he wanted and MS didn’t care to ask users beforehand.
The OP doesn’t say that they have a trademark. For me it sound as they don’t have one. Only a registered domain and the name of the software on github. The letter came on the grounds of the oponnents trademark.