The wooden spoon is no longer much done, but I think was really not the point of the comment.
Rather that kids were not always given the choice over what to wear.
That does not mean that they never were given the choice.
And tbh I have never seen any parent that actually gives kids complete autonomy about clothing. Even with regard to style, if they are taking their kids to something like a music competition, they are not letting them go in pjs, even if the kids want that.
The issue with "gendered" clothing is that if you create this sense that it is deeply important to avoid it in particular, it actually emphasizes the sense that non-harmful social conventions that reference sex have to align with some kind of inner feeling.
There is a reason so many parents who are very adamant about avoiding gender conventions with their young kids end up jumping on the gender ideology bandwagon.