Why do people assume that all bisexuals sleep with anyone that comes up to them?

To put it simply in two words and one sentence, it is because of their ignorance and fear of those considered into being differential in society. Although, such thing has been around since the beginning. Adding to this, it could also be from the label itself. The prefix bi- means 'two' and sexual is of relations to the two well known genders, male and female. People may think that because bisexuals deal with more than one gender, there could be multiple possibilities that they would not have a problem with dating everybody. It's like they believe that bisexuals would only be interested in participating in one big orgy of the two genders. But, in reality, it's not at all like that. Bisexuals, from the good ones I've known, just wanted to live their lives, and if they found a love interest in someone, they would do the same thing that heterosexuals do. Fall in love, try to be there for friends, love their families even if their families don't approve of their choices. Regardless of the bi- gender interests, it's practically the same thing, with a twist.

Because bisexuals have more people that they could possibly be in a relationship with, just because they like more than one gender, people seem to assume that bisexuals sleep around a lot. some do and some don't, just like any other sexuality. It's mostly just an uneducated idea.

People have unrealistic ideologies and you should not worry about that. Educate and move on. you dont deserve to be stereotyped.

I myself identify as bisexual, so I often find myself asking a similar question to myself also. I feel that people assume that bisexuals sleep with anyone that comes up to them because we are not definitively calling ourselves one thing. When you are heterosexual or homosexual you know exactly who we like, but as when people call themselves "bisexuals" I think certain groups of people look at that as the bisexual being confused and not knowing what they want.

They can't imagine what it's like to be attracted to different types of people, and they fear what they don't understand

It's kind of a 'you like more people, you get more people' type logic. It's similar to the stereotype that bisexuals have a larger dating pool than those who only like one gender (which is usually false considering some sexualities don't match up and biphobia is extremely prevalent). It's the idea that since we are able to be attracted to more people, we get more. It isn't true most of the time, but that's just the way it is sometimes. Also, we're in a pretty hypersexual culture, which doesn't always help.

I know, it's stupid, but I think it's because people think that since we will settle for two genders, that means that we will settle for any type of person as well, which is obviously not true.

I'm bisexual also, it's a development of biphobia, where bisexuals are told to "choose a side." Bisexuals have a bad rep (so do pansexuals) because some people don't understand that it's possible and okay to like people regardless of their gender; people can like others for the personality. They assume because they are critical to the bi community.

I know it's really bothering when people assume this, but many of them just do this out of ignorance, not malice. Bisexuality is a reality that not many people talk about, and it's easy to misjudge what you don't know. But we can help by doing our best to explain this reality to people who are willing to listen. You can tell them how it feels like, you can explain what it really means and help them overcome their prejudice through logic and knowledge. I know it's frustrating to do that so often, but if there's a chance that you can help people understand and stop judging, it's worth trying!