[Spexxvet]

When someone's beliefs are questioned, it likely causes some doubt. This person believes that his/her supreme being will protect them on earth and allow them to have a "good" afterlife. If the doubt makes them think that they will NOT be protected, and will NOT have a "good" afterlife, they become afraid, among other things. Fear causes them to strike out. The leaders know that if their followers have doubt, they may no longer be followers. This reduces the power of the leaders. So the leaders pre-emptively strike those who do not follow their "way", reducing the doubt/fear/threat to power. Possibly.