Let's be careful

If gender identity were only about social norms John Money would have been correct and David Reimer would have accepted his sex reassignment and childhood rearing as a female. Hence to simplify this issue to only socialization risks being simplistic. If there is some biological predisposition involved, this is why some are very much helped by transition. 

I see gender criticals only talk about social gender norms which seem to ignore the biology. The reason is they are trying to sell medical transition as being unnecessary. The Metaphor of Gender channel seems to be doing just that in arguing that dysphoria can be reduced to norms.

If there were no biology involved at all, then yes, transition would not be an issue since the person would live as they wish and ignore gender norms which some people do.

The problem for many transgender people is that this is not enough. 

Those who read my writing know that I am the last person to push for medical transition when it's not warranted, but to reduce being transgender to only a social choice is to denigrate what people go through. 

Those who want to bend social norms for a myriad of reasons are free to do so but they are typically not the ones reflecting on medical transition.