So, the end result of women with children's faces and grown up bodies is not a result of a fixation, but a traditional way of designing comic book characters. On top of that, the simplified facial expressions are faster to draw, which just reinforces the practice. That is why you see this style so often.
However, some artists do cater to "those" consumers, and will emphasize a child-like look using effects like bodytype/proportions, hairstyles, accessories and oversized clothing. Supply and demand...
Also, you did manage to find some of the more disturbing ones.