lifesavingnoodles - no, you're right there is no utopian world.
This world has bullies, abusers, rapists, murderers, people that pick their nose, people that lie, people that cheat, people that let others down and so on.
But that doesn't mean it's okay for us to swear in front of our children.
My attitude is not akin to refusing to warn children about speeding motorists - rather, it's akin to not speeding myself, least of all when I have children in the car.
Whereas your attitude is actually the equivalent of knocking a child over, or bullying one, or abusing one, or raping ones, or murdering one etc etc, in the belief that the have been better prepared for the world.
We have a responsibility to look after our children and yes, that means, hiding them from things until they are old enough to understand and deal with them. A parent unconsciously talking as though in the company of adults, when all they have with them is a toddler, shows that the parent doesn't understand that responsibility, or doesn't care enough about it simply to refrain from swearing now and then.
How you behave in front of your children either matters to you, or it doesn't. It really is that simple.