Nah, honestly he is pretty spot on. Telling a three year old that they can be a boy or girl if they want can have disastrous consequences later on in life. It completely fucks with a child's sense of identity. The reason he is being downvoted is because Reddit is so pro-trans at the moment that they don't particularly know or care about how that might effect a growing child.

That isn't even to say that there is anything wrong with being trans, I am very pro trans. The issue is that there is a lot of nuance to these sorts of things that a child really can't grasp at that age. They shouldn't be confronted with gender identity politics until they have a stronger sense of self and can decide who they want to be.

That said, it doesn't really matter how good or bad his argument was. It was better than the one you provided, which was non-existant.