Yeah, on the one hand I get that it's just easier to say, "Whew, they're Muggles. Don't have to worry about them." But then even she winds up having to deal with the fact that Hermione lies to them all the time and never sees them. She could have just made them parents who were rather pre-occupied, but instead she wants them to be these nice, normal dentists. Only those kinds of people usually have some clue about their daughter's life!