I don't spend much time researching those guys but I'm sure they did search the scriptures...So I don't know what they were wrong on...
But one thing I've found is that when people disagree on the scripture, it's generally not because they don't understand it...It's because they don't like what it says or don't believe it...So they change it to their liking...
See, I'm just the other way. My humbleness for being given the unmerited gift of faith makes me more charitable towards others who struggle in error. I don't assume they are deliberately wrong, but rather that they are a product of their training and influences.