I woke up thinking about this discussion which means I will walk away after this post, not to take my ball and pout, but really it shouldn't matter to me what people i don't know think about this, lol.
But it does. It does because boys deserve to become independent, and restrooming is a personal thing that a child should be in control of. Mommies are "protecting" their sons, not for the son's sake, but for their sake.
That said, to answer the question of the difference between boys and girls in this discussion, the answer is that the world isn't entirely safe. Nor is it entirely fair.
Boys are more often assaulted (sexually or physically) by known perps (like girls) but in less intimate places. Schools, churches, etc. Girls are in more danger in their homes, their relatives homes and their friends homes. None are in great danger in a crowded, well lit, populated Disney restroom!
Saying they are the same because both need to use the restroom and are thus in the same potential danger is like saying because both genders date they have the same concerns of date rate. It is just plain different.
So, we could not allow those situations, or we can give our kids the skills they will need forever. Building these instincts (which could occasionally lead to a child locking themselves in a rr, lol) is the only way they will gain the confidence in themselves to assess the situation and act on it.
Talk to the men in your life. Ask them how they feel about this issue. Ask them how they would have felt. This is a new trend which isn't good for our young men. We can't protect them from everything, wrapping them in bubble wrap.
Our kids aren't here to fill our needs. No one ever promised we would be comfortable doing so. They are just in our care while we teach them to be the best they can be. That is strong, self confident, caring people.