Women are more socially conscious. It’s a lot easier to control sexual access through women then through men. If you convince 99% of men to not have sex, the other 1% will just impregnate all the other women anyway. If 99% of women don’t have sex, almost no one will get pregnant. It’s way easier to control supply instead of demand.
Additionally, women have IUDs, birth control, the pill, family planning, female condoms, spermicides, tubal ligations, hysterectomies, abortions, etc. (though some of these are not available in South America) Men can get snipped (usually permanent) or use a condom (which often prevents orgasm). Women have more options in every conceivable way, which is probably why they are the target of these campaigns.