Who are They

[Ibby]

though the SPLC article linked above lays it out the best, imo.

Their disavowals of bigotry are belied by their actions: rank-and-file Proud Boys and leaders regularly spout white nationalist memes and maintain affiliations with known extremists. They are known for anti-Muslim and misogynistic rhetoric. Proud Boys have appeared alongside other hate groups at extremist gatherings like the "Unite the Right" rally in Charlottesville. Indeed, former Proud Boys member Jason Kessler helped to organize the event, which brought together Klansmen, antisemites, Southern racists, and militias. Kessler was only “expelled” from the group after the violence and near-universal condemnation of the Charlottesville rally-goers.