There might be more to it than that. Such people have always existed (males uncomfortable with male identity or roles), but the technology to permit them to live out their sense of self at a physical level has never existed before. They're going pretty nuts with it, but then again, I imagine people went pretty crazy with fire when they domesticated that force for the first time.

I've known also known some trans women personally; none of them listed shame at maleness as the reason they wanted to 'transition'. They just said they felt like girls and preferred life that way. Some were autistic and just didn't have a strong sense of gender, which is apparently common in that population.