> but now everyone agrees that was a huge mistake
Citation needed. Not everyone agrees.
> Maybe there are genuine disorders affecting some aspects of the less commonly found gender / identity phenomena. I'm not an expert. I don't know. I'm guessing you aren't either.
You don't have to be an expert to see the parallels between this and any other fad we've seen before, such as hipsters and goths and emos and punks.
> I'd prefer to error on the side of respecting the way someone feels
We're witnessing postmodernism today, where everything is relative, and no absolute truths exist anymore. What you mentioned is a symptom of that way of thinking.