Gender Identity vs Expression

I know identity and expression are different. People identify as a specific gender, or non-gender, by the way they feel inside. Expression is how we express our gender on the outside. This is tough for some people to understand because our society thinks it should always match up.

So I admit I had my own opinions on this. many people I know do express their gender by how they feel, and that is typically the gender they were assigned at birth. Of course I know many other people who don’t follow the traditional gender roles.

My point is this: 

My kiddo identifies as male most of the time and usually chooses clothes that are traditionally boys clothes. We still have a few shirts and shorts that are pastel or pink from when he was still getting hand-me-downs from big sis. Once in a while he will choose the girl shirt or short because either his favorite clothes are in the wash or they are just really comfortable. 

Now that he passes as a boy in public, people are confused when they see a ‘boy’ wearing girls clothes. Ugh. why do clothes have to be so gendered?! Why does it matter? I don’t know how to react. Do I say, oh he just likes them. OR, oh she is a girl.? 

Why can’t it just be clothes.