"When you believe in things you don't understand, then you suffer" -Stevie Wonder
I would say ideologies with the highest R0 values are the most dangerous. Christianity have almost identical R0 values, for virtually the same exact reasons.
They both are very attractive to the lowest common denominators. They both attempt to artificially level their respective playing fields. This appeals to people below the median line, and there are always more people below the median line than above it so this broad based appeal for a "free lunch" spreads like wildfire.
The Romans were confronted with this 1700 years ago and felt like they had to do something about it to control or 'own' it, thus the Nicene Creed., possibly the most dangerous ideology ever (a wolf in sheep's clothing).
Which ideologies do you think are the most dangerous? And is their danger a good or bad thing?
Which are most harmful?