No doubt in my mind that those early believers strongly believed, even to the point of death.
Cults, like Trump's personality cult, are all lead by one person. Waco is a popular example among the white nationalists. Ruby Ridge another.
The difference with Christianity is that many of its leaders died for their beliefs yet the number of believers grew. Obviously there are some sociological factors here as you and I have previously discussed.
IMO, like the USA is experiencing presently, it was a blending of cultures. Jesus brought something new, fair and loving. An attitude which conflicted with the "STFU, keep your head down and we won't kill you" attitude of the time.
The Bible, as well edited as it is, is just one book of many. If there truly is a God, wouldn't that God want us to learn as much as possible? Why else are we here? To sing Hosannas? LOL
The religious nutjobs, both atheists and theists, are free to rant, but as they always complain, "Don't impose your will on me!"
Like MAGAts, all the militant atheists on JPP are both hypocritical and very authoritarian. Sad. Weird, but sad.