I have an interesting theory about why religion has become so extreme. It is interesting to note that the great religious thinkers, at least in Islam and Judaism, used to combine religious thought with practical thought. What I mean is that human rationale was combined with divine commands. The Rambam and Ralbag are prime examples of this type of thought. True, there were always some divine decrees that we can't understand, but everything was looked at through the lens of rational thought. This is also where the idea of reasons behind the commandments come from. Both the Rambam and the Ramban say there are reasons for the commandments. However, more recently religion has disassociated itself from rational thought.
What do I mean that religion has disassociated itself from rational thought? I believe it all started when knowledge became more accessible to the masses. As the age of enlightenment dawned on man, more and more people began asking questions, logically sound questions. How did religious leaders respond? Most wrote these people off as heretics and thus, the leaders that took this path sent their followers on the path of non-rational observance of religious doctrine. However, there were some, like Rav Hirsch, that confronted these questions and found answers through rational thought.
This is what our generation has inherited from a long line of leaders that ignored valid questions, doubters with rational questions and followers that believe without rational thoughts. This leads to abandonement of the religion by people with valid questions and unquestioning allegiance to the religion by those that follow the religion. Hence, we are left with people that are willing to follow even irrational ideas in this religion. Therefore, if a leader tells one of his followers that stealing from someone outside the religion is acceptable, or even a commandment, then they will follow this leader. Basically, anything the leader says will be followed whether it is rational or irrational, logical or illogical.
This is basically how the shift to the right has occurred in orthodox Judaism. Many of the leaders in the past never dealt with rational or logical questions. They just dismissed the questioners or did not care to answer the question. This was very detrimental because it led to more and more unanswered questions that led to more people leaving observant Judaism, or to people abstaining from observing all the commandments. The most recent of these occurences was the Haskala movement and reform Judaism.
However, I believe there are some Rabbis that dealt with these questions head on and saved some of the Jewish community from these problems. Rav Saadia Goan, Rambam, Ralbag, Ibn Kaspi, Rav Hirsch, Rav Schwab, even Rebbe from the Mishna that explains why Dovid Hamelech did not really sin. All of these great Rabbis dealt with difficult issues, that were rationally difficult to understand, and explained problems with clarity and not ad hominum attacks against the questioner.
This is why I think extremism has grown, the communities that follow those Rabbis that never gave answers and wrote them off as heretical words are the extreme communities. They only require leaders that tell them what to do without any logical explanations. Their leaders could tell them that chicken is no longer kosher and they would immediately follow that leader.
There are communities that do have great leaders, but do not follow them blindly. In these communities the leaders words must have rationale and logic behind them in order to be followed. This is what Judaism is supposed to be about, rational thought. True, sometimes there are commandments from the Torah, aka G-D, that might not make sense to us, but that is a command from G-D. Every command that is man made, by the Rabbis, needs to have logic and reasoning behind it that is coherent and justifiable. Unfortunately, nowadays and even the past, some decrees made by Rabbis were unjustifiable. Burn the Rambam's books, they would say. When asked why they would say it was heretical. However, there is nothing that goes against the Torah in any of the Rambam's writings, just ideas that go against those Rabbis personal thoughts.
The difference, in my mind, between extremism and regular orthodoxy is simple. Regular orthodoxy realizes there are commandments from G-D that we can not understand. However, any man made commandments that the Rabbis instituted need to be logical and rational. The Rabbinic commandments are not on the same level as G-D's commandments. This is why Kavod Habriyos overrides the Rabbinic commandments. One is allowed to wipe his bottom on shabbos with a muktza object or be over some other rabbinic decree because of kavod habriyos (Allowing the created to have dignity). This is logical, the Rabbis commandments are to prevent us from transgressing a law from G-D, but they were not instituted for our detriment. This is a very logical idea, it is a prohibition to help protect us from transgressing a biblical law from G-D. The holiday of Chanuka is to give thanks to G-D for granting us an amazing victory and then causing the Menorah to stay lit for eight days. Makes sense. Also, the Rabbis are the ones that explain the biblical commandments to us. Even though the Chumash only says a kid in its mother's milk should not be eaten, it really includes all meat and milk for the reasons that the Gemorah goes into. These are all logical and rational ideas. True, it does require some faith, one must believe that G-D is real and wrote the Torah. However, I don't find that irrational or illogical.
The extremists, however, will tell you that the Rabbis words are the words of G-D and carry the same weight. Whatever their Rebbe says is the law and there is no bypassing it! My Rebbe says that you can not eat ketchup from the bottle with milk if when the ketchup that already came out of the bottle touched meat and my Rebbe said that you can not double wrap meat and put it in a microwave if it was used for milk dishes. How do these ideas make any sense? The ketchup in the bottle never even touched the steam of the meat. Double wrapped food does not communicate with the air outside and therefore not even a drop that could have possibly touched meat is touching a drop that could have touched milk. Why is that not allowed? They answer, because the Rebbe said and if you question that ruling then you are a heretic or you don't keep kosher.
That is just my take on the difference between the extremists and the moderates in orthodox Judaism. Anyone have any other ideas? Care to set me straight about something? Let me know.