Is Islamic terrorism worse than other terrorism?

I'm perusing a Congressional Research Service report on "homegrown jihadism" in the United States—it'll take a bit to digest—but I couldn't help but notice the kicker to this paragraph:

How serious is the threat of homegrown, violent jihadists in the United States? Experts differ in their opinions. In May 2010 congressional testimony, terrorism expert Bruce Hoffman emphasized that it is, “difficult to be complacent when an average of one plot is now being uncovered per month over the past year or more—and perhaps even more are being hatched that we don’t know about.”By contrast, a recent academic study of domestic Muslim radicalization supported by the National Institute of Justice reveals that “the record over the past eight years contains relatively few examples of Muslim-Americans that have radicalized and turned toward violent extremism” and concludes that “homegrown terrorism is a serious but limited problem.” Another study has suggested that the homegrown terrorist threat has been exaggerated by federal cases that “rely on the abusive use of informants.” Moreover, the radicalization of violent jihadists may not be an especially new phenomenon for the United States. Estimates suggest that between 1,000 and 2,000 American Muslims engaged in violent jihad during the 1990s in Afghanistan, Bosnia, and Chechnya. More broadly, terrorism expert Brian Michael Jenkins notes that during the 1970s domestic terrorists “committed 60-70 terrorist incidents, most of them bombings, on U.S. soil every year—a level of activity 15-20 times that seen in most years since 9/11.”  Few of the attacks during the 1970s appear to have involved individuals motivated by jihadist ideas.

So, no big deal then, right?

Now, it's true that jihadists scored one really spectacular attack with 9/11—and that attack, not all the small-bore and (mostly) ineffective operations since then is what we've decided to address with the creation of the Department of Homeland Security and the reorientation of our national security infrastructure over the last decade. It's understandable, if not always laudable.

But the truth is that 1970s radicals were, on an ongoing basis, more deadly than American-grown jihadists. And it's also true that a government agency that points out that fact feels compelled to add something along the lines of: "Sure, the radical hippies committed a lot more bombings. But they weren't Muslim or anything."