Certainly no worse than Scientology, and adherents of either face severe penalties for having the audacity to leave. How dare you leave us? We are a cult, you can't leave. We worship the only true god; all the rest of them are poseurs. We love you but if you leave us, we may have to kill you. My prophet is Jesus; mine is L. Ron Hubbard. In Jesus' time it took a while to develop a cult, but in the jet age (Hubbard hung around with rocket scientist Jack Parsons you know) that wasn't fast enough. Hubbard did it in less than a generation. Kazantzakis has Jesus surviving his ordeal, marrying and impregnating the Magdalene only to be told by Saul-Paul, the Zealot from Tarsus "you're supposed to be dead. You're of no value to us live." It should be easier now to see parallels between radical Islam and Scientology; both are cults, both are bogus confidence games.
Anyone who wants to denigrate me as an apostate and bring a noose can stare down the barrel of a Winchester 12-gauge. Sorry, fellas, I don't play your game.
We cannot compare the cruelty of Islam to apostates with any other religion or cult. The scale of Islam brutality to humanity is so huge. Thousands of people have been killed just for leaving and/or criticizing Islam. According to The Encyclopaedia of Islam apostasy “may be committed verbally by denying a principle of belief or by an action, for example treating a copy of the Kur’an with disrespect.”
In Figh(the body of Islamic law extracted from detailed Islamic sources), there is unanimity that the male apostate must be put to death. A female apostate, according to some Islamic sources, must be imprisoned and according to other Islamic sources, she also must be put to death
If that is the case, then any time anyone CHOOSES (do please mark that word) to leave their religion, and a religion or government decides to penalize them for that choice, then attention, unblinking, laser-like attention, MUST be drawn to that situation and to that person. And if that religion or that government opt to execute that person, then there must be a price to pay ... and that price should be high ... indeed, that price should be EXORBITANT!!!
It's not just the extremists who are cruel to apostates. I've heard so many times that Malaysia is a "moderate" Islamic nation, and yet they have horrible government regulations against apostasy.
It should be noted that there are essentially two citizenship classes under their system of ketuanan melayu, and these classes are mostly race-based. Only ethnic Malays are granted the full benefits of citizenship, but their view of ethnicity is messed up beyond all recognition. To be a "real" Malay, you must also speak Malay, observe Malay cultural practices, and be a Muslim. To give up any one of these is to give up your right to full citizenship and a whole host of government benefits. You might have to pay up to 15% more for housing. If you want to send your kids to public college, they'll have to compete for the few leftover spots because the government will sic a giant mutated affirmative action monster on you. There are strict quotas with something like 90% of seats reserved for ethnic Malays... who make up the majority of the country. Peaceful protests are met with tear gas and acid water.
A while ago, there was a Malaysian woman who petitioned to the government to remove her Islamic status because she had left the faith. The response she was given was basically that if she really wanted to go through with that, it would mean giving up "Malay" as her ethnicity and she would be issued the second class citizens' card given to the non-Malay population. Maybe by "moderate" they mean Malaysians won't outright kill you for leaving the faith, but there is still so much overt bias written into their laws. I can't understand why anyone would point to Malaysia as an example of how peaceful/loving/understanding Islam is.
Edit: The education quotas were removed in 2003. But not really - they just moved the practice underground. There are still Malay-only institutions.
I assume that the memetic viewpoint is alien to most members of this group. Any culture where mere disrespect of the dominant religion is harshly punished would find the idea that all religions are like parasites of believers so unthinkable that memetics would never be publicly discussed. For an introduction see Wikipedia Memetics.
I view religions as mind viruses. Just as some viral diseases are more virulent than others, some religious memeplexes perpetuate themselves in their human hosts by severe penalties for "recovering from infection". There is no "why" in my view, because these horrible rules evolved through memetic evolution. Memeplexes are informational entities, capable of neither cruelty nor compassion (though their infected hosts can have these feelings). Versions of Islam with death penalties for leaving spread faster than those which did not, or perhaps they were more resilient to exposure from other religions. Hosts can be manipulated by fear. It works. If painting the third toe purple made Islam spread faster, millions would have purple third toes. Reasons aren't needed. Explanations which look for reasons miss the point. Mind viruses don't have "motives" or consciousness or morality in the same sense as human beings. They evolve, they mutate, some mutations spread faster. It's evolution of cultural bits, self-replicating chunks of information such as words, images, songs, ritual practices.
Seeing religions as memeplexes removes the respect and awe we hosts have been tricked into adopting toward them. Compare religions to computer viruses and biological viruses. It's illogical to revere them. I don't give them the respect due a moral agent. The question "Why is Islam too harsh and cruel to apostates?" presumes that Islam can be considered a moral agent. Viruses are neither moral nor immoral, they're just parasites or at best symbionts.
Islam does not deserve the respect implied by this question.