Definition of fascism (from Merriam-Webster online):
1 often capitalized : a political philosophy, movement, or regime (as that of the Fascisti) that exalts nation and often race above the individual and that stands for a centralized autocratic government headed by a dictatorial leader, severe economic and social regimentation, and forcible suppression of opposition
2 : a tendency toward or actual exercise of strong autocratic or dictatorial control
Well, if you don't know anything about Islam, you might think that Al-Qaeda or Iran or the Taliban might fit definition #1. Islam, however, does not seek to exalt any nation or race above others. Even to Muslims, Islam does not equal Arab (as it does to so many ignorant Americans). Most Muslims aren't Arabs. Iranians are Persians and Afghanis are a bunch of different ethnicities. Also, they don't support dictatorships. The history of modern Islamic radicals is of them seeking to overthrow the dictatorships that rule their countries. The Taliban didn't center on one individual, nor does Iran. Al-Qaeda might...but it's stateless. They're not even eligible.
You might wonder why liberals are all up in arms about something that's just a word, after all. The problem is that this misusage isn't a mistake or an error. It's a deliberate effort to control the language of the debate and set the terms so that dissenters are standing on ground that conservatives control. Christopher Hitchens is often heard spouting off this phrase, and recently George W. Bush was heard using it as well.
As I said earlier, the point is to deliberately conflate two different enemies and ideologies. There may be more than one reason for doing this. According the article I just linked:
So why would the president, no master of words even when playing his hand well, employ such an easily knocked-down concept to characterize what he obviously means to be the next target of his imperial wars in the Middle East after Afghanistan, Iraq and now Lebanon? Simple. Because he thinks it links him to his father's great cause, World War II; it makes any destructive thing he does acceptable, and at a time when most Americans want to lower the stakes, it gives him reason to up them.
According to the Wikipedia entry:
The use of the term "Islamofascist" by proponents of the War on Terror has prompted some critics to argue that the term is a typical example of wartime propaganda.
"Islamofascism is nothing but an empty propaganda term. And wartime propaganda is usually, if not always, crafted to produce hysteria, the destruction of any sense of proportion. Such words, undefined and unmeasured, are used by people more interested in making us lose our heads than in keeping their own." —Joseph Sobran, syndicated columnist.
I think that the latter explanation is definitely the case, although for President Bush equating himself with his father is certainly a benefit. It's not necessarily a deliberate campaign of propaganda by all who subscribe to the idea behind the terminology, but there certainly are those out there who are pushing it.
This is no defense of those vile Islam-based regimes such as the Taliban or Iran, but it doesn't do the world any good to so grossly oversimplify the issues. Hezbollah is not Iran or the Taliban. You can't treat all the Islamic radicals the same, and it is only a disservice to American diplomacy to try and say that you can by shouting slogans as if that makes it true.