I came across an article on Yahoo the other day entitled "How much is a homemaker worth?"
Everything listed in this article (except for child care) are all things that single people do as well, but we never see articles saying single people should be paid hundreds of thousands of dollars for doing things that are part of life, and that everyone (not just mothers) has to do. We don't try to self-aggrandize and call ourselves house cleaners just because we cleaned a toilet.
If we follow this logic, I'm a sanitation worker because I flush my toilet. I'm a dog groomer because I bathe my dog. I'm a financial planner because I set myself a budget. I'm a personal shopper because I buy groceries. I'm a personal trainer because I work out. I'm a pastry chef because I bake cookies. I'm a meteorologist because I look outside and say "it's raining".
It all sounds ridiculous, doesn't it? Is that because I don't have children? Would any of the above be true if I did? No, because I don't have the training to be any of those things. I haven't earned the title.
It's no secret that if you have kids, you're going to have to cook for them, clean up after them, and do their laundry, so why do mothers expect praise and admiration for something they chose to do?