People from all around the world and all throughout history have had a lot of crazy beliefs that lead to all varieties of interesting behaviors.
The Aztecs cut hearts out to ensure the sun would rise,
Some places in southern India toss babies off of temples into blankets to make them stronger,
Jivaro people of South America would cut off the head of a slain enemy and then shrink them to prevent the soul from getting revenge,
According to some Islamic writings, every man who dies for jihad will be given 72 sex slaves,
Jain monks wear cloth masks to prevent the accidental inhalation of flying insects who may be reincarnated ancestors,
Many Christians believe that at any moment the rapture could happen, saving them from their suffering,
And Scientologists believe... Where do you even start?... well, whatever they believe it's obviously a money grab.
So, is it OK to make fun of these beliefs, especially if they are dangerous?
I would argue that some of these beliefs lead to violent or destructive behaviors, and by making fun of them we can prevent people from falling for such non-sense. In this way the religion will slowly lose power over time and it's influence will dwindle, and people can focus on making rational life choices.
At some point in the distant past, the universe went through a phase of cosmic inflation, Stars formed, planets coalesced, and on at least one of them life took root and developed into the human race, who conquered fire, built societies and developed technology .
All of that so we can argue about nothing.