Slut-shaming is a recurring issue in a lot of fanfictions: when a girl, except the female main character (or a friend of hers), gets in a sexual relationship or starts flirting, she’s depicted, at best, as a floozy.
The logic behind this bad reaction is hard to understand. On the one hand, we may think authors see women as the chaste and passive ones in a relationship. On the other hand, we may find female main characters who betray their boyfriend without a second thought. At this point, it sounds more like spewing hatred at the world.
Now, Sailor Moon. It is an anime where the main characters express their sexuality without receiving any discrimination.
Makoto/Sailor Jupiter is the most striking case. She finds something of her ex-boyfriend/senpai in any guy she meets, whom she readily flirts with. Venus and Mars are no different. However, nobody says anything to them. Mercury is shyer and, once, she said that going after guys is wrong, but this is “her opinion”: she doesn’t pursue that behaviour, but everyone is free to choose and do it if they so want. She waits for when she’ll find the right guy, but she is a loyal friend.
Sailor Moon, as well, could get mad if someone flirts with her boyfriend, but she doesn’t verbally offend anybody and doesn’t show hatred either. She could butt in, make a scene out of jealousy, but still, it’s obvious she takes it lightly. If the third wheel turns out to be the victim of the situation, she helps them without a second thought. As I mentioned before, there is an abyss between getting annoyed because another girl is flirting with your boyfriend or acting like a fanfiction’s female main character (aka Hope) or a bad boy.
In this context, Uranus and Neptune are the more mature ones. Sometimes they choose to flirt with someone else, but they both take it lightly because they trust each other. At most, they argue in private. However, such fights are still trivial things; it is nothing serious.
Even in the fourth season (which is a low-quality filler because even the manga’s author didn’t know how to continue the plot), the topic is handled in a fair, mature fashion.
Sailor Venus/Minako is dating two boys at the same time (the two of them turn out to be villains in disguise, but this is another story), and she gets judged for her behaviour by her friends. Knowing the characters and their way of acting, the fact of flirting with two different guys is not the point; rather, it is not clear if the relationship is a serious one. We all agree that a teen, who finds out that the girl he is dating with is seeing someone else she has never told him about, could be very, very upset. In the end, it is a matter of honesty and respect, and Minako is out of character in this context, in my opinion (in the previous seasons, she was silly but mature).
In the fifth season, there is a devastating change even regarding this topic (Uranus and Neptune become close-minded towards other alien warriors, and the prior has even a violent attitude, close enough to a fanfiction’s bad-boy behaviour), but this is due to some changes in the direction and plot stretches.
As you can see, examples of respectful attitudes have been a part of popular culture for many years. Yet, they are often overshadowed by much poorer and still equally famous, if not more popular, products (any reference to Fifty Shades is intentional).