There are already words for all of that though, like Wahhabism, radical salafism, etc (most of which are ideologies that predate the Nazi party, FWIW). It's not like the idea of an Islamic state conquering huge swaths of land, forcing all the people to adopt their ideology, and taking out people of other beliefs is a new idea or anything. Of course, Islamo-Nazi makes for a catchier headline and requires no understanding of middle eastern history or culture, so I can understand why some would cling to it so tightly.
I don't really have a problem with using the Nazi party as in a compare/contrast to explain to people what some radical groups envision. It's probably a really useful way to explain things to someone who isn't well versed in the history/culture of the area. I just find it funny that some will attach themselves so tightly to the term.