Pansexual is, at best, just another term for bisexual, but to sound more special and exotic. Especially since the B crowd is something of a black sheep in the alphabets. Gs and Ls don't like them because they view them as daywalkers who haven't fully committed to the cause, and the rest hate them the word itself acknowledges the sexual binary they hate so much and want to think has never existed.

Alternatively, it's just a lie to say they don't take physical characteristics into account when seeking a partner, which is complete bullshit. They just don't want to admit that what they really have are some very fucked-up fetishes.

At worst, it's a subtle admittance of being zoophile, necrophile, or pedophile. After all, they are capable of loving everyone regardless of their appearance and physical attribute. And "love is love" after all, right?