A pan exclusionist or BaB (Battleaxe Bisexual) is someone who believes that pansexuality, omnisexuality, polysexuality and other m-spec labels other than bisexual contribute to biphobia and transphobia. They also believe that m-spec labels are the same as bisexual. These individuals typically try to educate people who identify as or support m-spec labels, but mostly focus on pansexuality. Not all pan exclusionists are BaBs, however most of them are.
It is mostly radical pan exclusionist or radical BaBs who are known to doxx, harass, and send death threats to supporters of m-spec labels or those who identify with them. They in no way shape or form represent BaBs. Real BaBs, as earlier stated, try to educate people on the history of bisexuality, and pansexuality and its flaws. They try to at least get people to acknowledge the flaws in pansexuality and other m-spec labels. They don't try to convert pansexuals to be bisexual or try to invalidate their attraction. They only try to educate.