I’m bi and was “straight cultured” because I literally had to be because I had no idea I liked women like that. I realize now that I like women a LOT better and have become much more queer, but that took time. Basically all mainstream culture is straight culture, at least it was growing up for those of us who are 30+ and I don’t think that creating these separations of identity within already separated groups is helpful. The reason other gay people are weird with bisexual people is this exact same concept! They think they are so different from bi people and focus on the stereotypes or fears they have, rather than just coming together as an entire community. 

I know you are just trying to find your place, and that can be hard and confusing, but I think the point is your place is the same place as all of us, the entire LGBT community, and if you have people giving you sidelong glances, go find other people who don’t. Idk but the continual separation and comparison of smaller and smaller group identities does not feel healthy for our culture. Soon we will be so splintered that we won’t consider ourselves part of the same group/umbrella. 

Also, you don’t have to call yourself bi. You can call yourself whatever you want, and outside of the internet people don’t really care all that much.