Jim Jones was a classic cult leader and yes most of those people were brainwashed. The man was very charismatic. While in the states he had a way of making people like and believe him. He had many very powerful friends and supporters in the government and other powerful positions until some began to realize he was actually insane. I was barely ten when that thing happened but it was huge news and it made a huge impression. He moved his cult to Guatemala (i think) build Jonestown to escape govt prying in the US since by then many of his former supporters were finally seeing him for what he was, a megalomaniacle nut. Once out of the US those hundreds who followed him were even more under his control. When he decided it was time to leave the earth he fed all his followers poisoned red coolaid. Just in case a few changed their minds and didnt want to participate he had his guards armed with automatic weapons. .
Most people do not realize they are in a cult, but the leader of the cult knows they are in it. The leader brainwashes people into being in the cult ,and they unknowingly accept. Now I'm not sure what happened with the kool aid, but you shouldn't take any sort of food or drink from strangers, always remember that.
Stupid. If they had read the Word ( The Bible ) they would of known He was preaching false doctrine, The Bible tells us it's better to Trust in God than put confidence in man. Psalm 118.8 And it also says to test the spirits to see if they are of God.
1 John 4:1
4 Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world.