I am fully supportive of grandkid being the best, most comfortable person they can be. By being comfortable, they can thrive.
But I see where others are having problems reconciling the gender change. At best, these concern trolls think about the generous, happy appearing little six year old girly girl and this whole situation seems like Teen Angst or acting out - and lots of parents who might otherwise claim to support their kid, don't want their kid to set themselves up for bullying.
Oddly enough, they don't seem to care much about Trans Males ("That's just being a Tomboy, she'll grow out of it..." ) but Trans Females - oh, no...
A lot of the problems with the general public is they may accept the LGB, but they think the T is play-acting or Pantomime, like Dame Edna.
Which is odd, because throughout history (at least in England) there were apparently people who legally changed their genders and would occasionally go so far as to put out announcements in small, local newspapers that they were now legally "Miss Elenore X" or "Mr. Edward X".
Thanks to J. Draper - Nebula, YouTube, and TicToc - on her excellent video studies of English Social Mavericks and customs throughout history.
I have heard more than one feminist express that Trans Females are a character - basically Drag Queens - play-acting and exaggerating femininity for their own amusement, which is offensive to "real women" in the "real world".
While otherwise liberal men have problems because they think they're going to be tricked by a pervy Gay man preying on straight men.
Liberals are not immune to personal stereotypes and bigotries. We are all just people, after all