Biphobia is a thing and it is a thing in gay/lesbian communities just as it is among straight people and your statement demonstrates why that is: straight people just see bisexuals as gay or lesbian and gay or lesbian people see them as traitors or cowards, especially if they live in a stable "straight passing" relationship.
Bisexuals aren't just "homosexuals who aren't committed enough". Research dating all the way back to Kinsey demonstrates that most people aren't fully hetero- or homosexual in whom they find sexually attractive regardless of what they identify as. If anything, "fully" homosexual or heterosexual people would be expected to be the exception if there were no hangups around these labels and identities.
> desperate to cling to something that makes them a victim in this world
There's a grain of truth in this perception but sadly it's tainted by American culture war bullshit. Teens and young adults have always experimented with identity and social roles so it's unsurprising they'll "try on" identities relating to themselves and that some of them will be whatever gets hotly debated today.
But this is very much a "now that we have stopped physically punishing children for using their left hand all of a sudden everybody is left-handed" dynamic to this, too. Social acceptance of left handed people led to a sharp increase in the number of left handed people followed by a period of stabilization leading to a steady proportional demographic because there were already left handed people living "in the closet" (knowingly or not) and they were finally able to "come out" once being left handed became socially acceptable. There were probably also some people unsure if they may have been left handed all along and giving it a try to see what felt more natural and then settling one way or the other, but left-handedness wasn't a "trend" or a "social contagion" or an "epidemic", just a way of being human that was previously suppressed and now normalizing.
And even today left-handed people encounter some discrimination or bias (intentional or not) in their daily lives. Utensils may still be needlessly tailored to right-handed people or left-handed alternatives may be unavailable simply because nobody considered the need for them or left-handed people are just expected to make do because they're a minority and shouldn't cause a fuss (and they can just try to use their right hand anway, right?).
But it would probably sound ridiculous to you if I said "I think kids these days are just claiming they're left-handed because they want to be victims" -- and I don't think it would have sounded as ridiculous when left-handedness was only just gaining acceptance and there was a sudden massive spike in the number of people claiming to be left-handed.
So here's a thought: why are identities like being bisexual (which if we can trust Kinsey mostly just means not making any assumptions about who you might find attractive by gender alone) considered "victim" roles? If it's because they're being treated badly, why don't we just stop treating them that way? So what if it means some kids who were "only doing it to be the victim" end up being caught in the crossfire and end up being victimized less?