cant we leave children the world over to make their own minds up when old enough to decide what makes sense to them?

Religion can't afford to do this, achmelvich. Say you waited until your child was eighteen, then invited him to join an organisation as corrupt, undemocratic and authoritarian as any big religion (naturally, being an open-minded person, you would have to represent your faith of choice honestly to your kid). You wouldn't get many to sign up. The only way religion can hope to perpetuate itself is by signing up babies en masse. They all do it, don't they, and you won't find many adherents who see anything wrong with it. Amazing how you can adjust your morals to suit!