I like these ads because we don’t often get to see this portrayal of little girls on this site. It is so easy to put them on a pedestal and forget they play on the ground like the rest of us. I also want to commend the advertising companies for their clever manipulation here.
The expectation is for boys of any age to be getting dirty playing sports. Using the girls gives the company two advantages: 1) They can seem wonderfully egalitarian while 2) exploiting the extra charm that only little girls have. If little boys got dirty like this, a mother might be inclined to just let them stay that way and that doesn’t move product. The use of girls plays on the stereotype that even though it is OK for girls to get dirty in this day and age, it is also important to clean them up and turn them back into little princesses again. This subtle motivation gives the reader that extra push to buy cleaning supplies.