I guess all terrorism is political to some extent, but I still don't see a direct comparison here.
You could describe Islamists as religious fascists, but they do refer directly to their God when they carry out atrocities. I can't think of an atheist ( anti-theist? ) equivalent, I haven't heard of any terrorists shouting "Death to God" or something similar before they blow themselves up.
I'm not arguing that Islamic fanaticism has a mirror in 'atheist' terrorism, since atheism, in and of itself, is not a motivator of anything. So no, I couldn't see atheist terrorists shouting 'Death to God' even if such a statement wasn't contradictory with atheistic non-belief.
I guess my points were twofold;
1) People talk about 'theistic' terrorism, but, despite being theists, I can't name a Jain terrorist. If I look at Christianity, there are particular denominations which have not spawned terrorists and some which have. 'Theistic' terrorism is an oversimplification. The nature of the beliefs themselves and the societal/political context matter. So sure, I'm fine with rejecting atheism as a motivator of terrorism. But I'd suggest that theism is not a motivator either. Instead, people have more specific ideologies which motivate terrorist acts. Marxist-Leninism is an example, so too are some brands of Islamist belief. In drawing that parallel I am not suggesting the two represent an equitable threat to global security, but I think this approach fits well with both historical and modern terrorism.
2) I am hesitant to make points for
@Laika, since I am more suggesting there is material here for a decent discussion, rather than having a formed opinion. But atheism IS a factor in decisions people make, even if that is only by the omission of other beliefs. Think of it this way...take 4 people and place them into the exact same political situation. Of the 4, one is a Islamist (an extremist), one is a pagan, one a Jain and one an atheist. If the religious beliefs of the first 3 impact on their decisions, then it is a useful (if technically inaccurate) shorthand to talk about the impact of atheism on decision making for the fourth. In truth, we are talking about the lack of religious factors To me, this is a neutral statement.
If a completely ham-fisted and stereotyped example helps, the Islamist's belief in a 'higher truth' can enable more extreme actions, whilst a Jain's extreme pacifism could lead to inaction even in the face of extreme provocation. The atheists atheism (in and of itself) offers no real indication of ideology. IN much the same way, if I said there was a theist in the room, but didn't state anything more about them, it wouldn't be indicative of possible behaviour.
I hesitate to guess what the pagan might do, since 'pagan' is a borderline useless term when it comes to ideological predictability. Almost as useless as atheist.