Calling it an extreme connotates it as "wrong" to a degree, when other philosophers might counter that there is just the right way and wrong way i.e. Kant's Categorical Imperative and its Universal Moral Law. I do not totally agree, or even understand, the implications of Kant's pov. especially the example of a Nazi knocking on one's door, one is universally morally compelled to say you are hiding people. However the intention of these "extreme ideologies" is not to create useful/practical approaches to life or thrive in society or even be happy, but to uphold values which may be greater than life itself.