Totally agree with cassieohpia and suzifrommd, and with Lauren and Maddy's comments on that original link (didn't read the comments beyond those).
If all it takes is anecdotal evidence, then I think I have found enough anecdotes in the last few days of being here of people who were doing well enough socially, professionally and in their family lives that they shouldn't have even thought about transitioning or gender dysphoria, if it was only a psychiatric issue. There are enough examples of people with loving parents and well-nurtured childhoods who don't have a whiff of any psychiatric issues, but they do deal with GD and being TG/TS. And there is at least some scientific evidence of non-obvious biological reasons for GD (maybe not enough to be regularly used for diagnosis, but it exists nevertheless), which this person with '30+ years in the profession' seems to have missed, or deliberately ignored.
His post just seems like a lame excuse to take cheap shots at people with differing opinions.