Firstly, IMO there's just as much chance that these people talk absolute rubbish (or, say Jesus existed), than there is that they're not.
I see as us being "science/logical"-ists, but then that is what we see, and have been taught. From an individuals point of view, they are both the same, no?
Take death. For "people like us", we just disappear and physically disintegrate with no notion of afterlife.
Who are we to say these 72 virgins/heaven & hell (in whatever incarnation) don't exist?
I (try to) say live and let live.
Secondly, and in agreeance with Mr Sun, It was not religion which caused these people to do those atrocitiies, it was their ability to be weak or impressionable to be taught their beliefs which lead them to be suicide bombers. That's why I find it hard to get worked up about punishing them (althoguh now we know they were suiciders etc). Surely they had somewhat of a "diminished responsibility", although it could be argued that they were negligent for putting themselves in a position to get brainwashed. A whole different argument (isn't anyone (most) who murders insane etc?)
I'm sure everyone here's made a decision, say, when in love, which looking back, was laughable. Well, just think, that was just over "some bird (or fella)".
Imagine if someone who was a respected member of your community, and in fairness, a leader of everything you base your life around (i.e. head Muslim Honcho), (bearing in mind the fact their faith plays a much more important part in their life, more than women/work/cricket etc), (gradually, and with a very skilled method of teaching and maniulation) lead you to do these things. It's simply not that unbelievable.
Imagine if your Dad (or close family member) asked you to do somnething you'd rather not? Of course you wouldn't, but you can imagine over long term him fashioning your beliefs so from ridiculous, it becomes odd, then oddly believeable, then reasonable, then...
Sure Islam is the domain from where these people come, and it is religion which is the background to which these people can be brainwashed, but then the next logical phase of the argument is "Well, wouldn't it be better if we had no religion at all?", to which the answer IMO is a resounding Yes.
Purely on the basis of numbers of "normal" religious people, and the good it does them. It's hard to see in the light of recent (last 100 years even) poor effects religion has had on modern society. It has been the basis of our moral and ethical teachigs and law, and without it, we simply would not have the social cohesion and even technology we enjoy. Society, like it or not, IS based on religion.
Granted I see religion having a less and less influence on our life going forward long term, but then ask yourself what fills the void?
DO people just stop "believing" in something? No. Something will need to gradually take it's place, be it, say football team, geographical location (again), or, more realistically, Political persuasion.
Even from my point of view, I'd see much more reason for someone to start a bombing campaign on the grounds of getting someonw to "agree" (submit) to their political view. (although yes, it's conceeded that perhaps the sense of "afterlife" is that which primarily encourages suicide attacks).
Some people are just nutters. Simple as. You can't control it (ulitmately), legislate for it, or allow it, but you can expect it IMO.
Religion or not.