We've seen lots of videos of Palestinians firing rifles in Jenin (and elsewhere). Clearly they are not mere stone-throwers.
The Jenin Brigades - a group of men with weapons - sometimes issue statements.
Here they are from another recent photo:
They have certainly fought against and arrested Hamas and Islamic Jihad terrorists in the past. Now, they seem to be OK with this group.
Either the PA has decided that Islamic Jihad is an ally, or they quietly hope that Israel will uproot them from Jenin and while they publicly protest Zionist incursions and quietly celebrate.
But either way, the Palestinian Authority is not indicating any opposition to having a mini-army in their midst. Tolerating it now allows it to grow, especially with the current propaganda blitz around Abu Akleh's death and the boasting about the death of Noam Raz that is starting to spread in Palestinian media.
Of course, no Western media is even asking the basic question of how a heavily armed group could spring up in Jenin while the well-funded Palestinian Authority security forces do nothing.