1. More sex = less conflict.
As the great primatologist, Frans de Waal put it, "Chimps use violence to get sex, while bonobos use sex to avoid violence." While chimps victimize each other in many ways—rape, murder, infanticide, warfare between groups—there's never been a single observed case of any of these forms of aggression among bonobos, who are much sexier than chimps. As James Prescott
demonstrated in a meta-analysis of all available anthropological data, the connection between less restrictive sexuality and less conflict generally holds true for human societies as well.
2. Feminism can be very sexy. When females are in charge, everyone lives better (including the males). While male chimps run the show, among bonobos, it's the females who are in charge, with much better quality of life for everyone involved (see #1).
3. Sisterhood is powerful. Although female bonobos are about 20% smaller than males—roughly the same ratio as in chimps and humans—they dominate males by sticking together. If a male gets out of line and harasses a female, ALL the other females will gang up on him. This sisterly solidarity, combined with lots of sex, tends to keep the males behaving politely.
4. Jealousy isn't romantic. While bonobos no-doubt experience unique feelings for one another, they don't seem to worry much about controlling one another's sex lives. Nor do bonobos seem to gossip much...
5. There's promise in promiscuity. All the casual sex among bonobos is arguably a big part of what has made them among the smartest of all primates. Until human beings came along and messed things up for them, bonobos enjoyed very high quality of life, low stress, and plenty of social interaction in hammocks. In fact, of the many species of social primates living in multi-male social groups, not a single species is sexually monogamous. Each of the arguably smartest mammals--humans, chimps, bonobos, and dolphins—is promiscuous.
6. Good sex needn't always include an orgasm, and "casual" doesn't necessarily mean "empty" or "cheap." Most bonobo sexual interactions are nothing more than a quick feel, rub, or intromission—a "bonobo handshake," if you will. (See Vanessa Woods's excellent book by that name for a personal story of living with bonobos while falling in love.) But bonobos are very romantic: like humans, they kiss, hold hands (and feet!), and gaze into one another's eyes while having sex.
7. Sex and food go together better than love and marriage—at least for bonobos. Nothing gets a bonobo orgy started faster than a feast. Give a group of bonobos a bunch of food and they'll all have some quick sex before very politely sharing the food. No need to fight over scraps like a bunch of uncouth chimps!