>>43572913In a word, competition. Females of most human species will backbite and try to undermine each other on instinct without even consciously realizing it. The feminine imperative is baked into the brainstem. A woman seeing other women raising their value is by extension seeing her own value being lowered by comparison.
Another part of it is projection, and this is something both men and women do.
Ie, the assumption that what turns them on is what turns the opposite sex on too.
For example,
>>43572970Women are impressed by men who can defy them, and therefore assume the same behavior is attractive to men in turn (it's not).
Body count is another classic example. Men are repulsed by high body count women, and therefore often tend to avoid mentioning relationships, past or current, with other women, thinking that this is repulsive to them too; but women are impressed by men with high bodycounts, and will often make the mistake of mentioning past experience to current flings (or worse, current experience to current flings), unconsciously assuming men will be impressed by this too (they're not).