Certainly this is a far cry from burning apostates alive or beheading them, but it is still an unusually aggressive response against apostates.
Another similarity is that Scientology, like Islam, tends to paint itself as the underdog, an effective way to simultaneously unite believers together and disarm unbelievers. Scientology and Islam both attack those who criticize their religion and try to suppress negative information, and they do it in similar ways. Scientology tried to smear the filmmakers, for example, in an effort to discredit the film (read more about that here). And they tried to prevent the film from being shown (read about it here).
The documentary is based on a book by Pulitzer Prize Winner Lawrence Wright, who also wrote an exposé on Al-Qaeda entitled, The Looming Tower. Going Clear is driven largely by interviews with people who were in Scientology for a long time and sometimes held high rankings within the organization, but who have left the religion. It was very well done and interesting throughout. Wouldn't it be great to have a similar documentary about Islam, just as well done and just as straightforward?
A point we've made repeatedly is that a useful strategy (when talking to others about Islam) is to switch to talking about Scientology when you meet resistance. People have no problem listening to criticisms of Scientology. You can then follow up with similar comments about Islam, and you can often avoid resistance because why shouldn't you be able to criticize any religion as freely as you can criticize Scientology?
Recently I've talked to people about Going Clear, and then as an aside, when I mentioned something about Scientology's policy toward apostates, for example, I point out that it is a similar but milder version of Islam's policy. It is an easy way to slip some solid information into someone's mind without much resistance. Whenever you criticize Scientology, you never hear any objections like, "But isn't that just a small minority of extremists?" or, "What you're saying is racist," or, "Are you a Scientolophobe?" People are completely at ease with even harsh criticism of Scientology. We can use that to our advantage. Learn more about this approach here: Scientology and Islam.
In the last scene of the film, one of the interviewees was asked why she was speaking up about Scientology (and potentially exposing herself to harassment and danger). She said simply, "I just want the truth to be known." That's how we feel about exposing Islam for what it is.