They're mad that the facilities are not releasing the (highly contagious) bodies to the dead person's family for "proper" burial. The facilities are instead following proper protocol, and burying the bodies safely. Some of them honestly believe that Ebola isn't real, and is instead a scam by white westerners to steal Black bodies for nefarious purposes.
It's literally just ignorance and paranoia. They're attacking the very people who are helping them, because of a conspiracy theory and a lack of education.
I was in Sierra Leone during their outbreak in 2015 (I'm not a healthcare worker, but I was there to feed the healthcare workers), and we faced similar challenges. We had to cancel our mission because we were attacked so many times, and it wasn't safe to be there.
It's actually worse than that. They want the (highly contagious) corpses of ebola victims to be released to the families, so they can have a heckin' proper (religious) funeral.