It COULD just be a straight up scam, with the "older/average/plus sized/bored single mums" description there to make it sound slightly less than too-good-to-be-true.
I also recall hearing an explanation, I can't vouch for it being bullshit or otherwise, that there are two separate fee-paying dating sites set up. One is aimed at men, suggesting a surplus of easy women looking for no-strings sex. Another site is aimed at women, promising eligible/rich/divorced/retired bachelors looking for marriage/kids/spoil them with gifts. Give these two completely mismatched groups access to each other, and pocket the money.