I'm not religious either, but I don't think it's really appropriate to put the blame for terrorist attacks on religion in general. The vast majority of religious believers are peaceable people, even if we don't share their beliefs and practices. Terrorists use their distorted view of their particular religion to persuade others to join their violent cause, so the blame lies with the terrorists and their gullible followers.
For clarity,
I did not call ALL believers Terrorists BUT religion in all forms has been used as an excuse for everything from War downwards throughout history.
It is a so useful way to 'rabble rouse' a group of 'peaceable people' into an avenging mob.
It is the usual process of identify the differences (any will do) and demonise the non-believers.
You then direct (mis-direct) the angry people to do your 'real' objectives in the name of supporting/protecting your true faith.
This has been done by all the major religions throughout history.
This history feeds into the rhetoric, to fuel later acts and so on and so on.
Today we still have it very visible in everyday life in places like India/Pakistan where people are killed for daring to criticise things done in the name of various religions.
The on-going Kashmir dispute has been turned into a religious dispute because of the majority split of religions in India/Pakistan (Hindu/Muslim)
Various Terrorist groups are in existence in areas policed by Pakistan (supposedly) these groups are fighting a religious war (supposedly).
The Israel - Palestine dispute is also a Religious dispute as both sides in desperation to push for greater support have more and more focused on the two main religions as being attacked and under threat.
You will also note that the settlers that are mostly pushing the frontiers of the Israeli state are the Religious fanatics within Judaism, as more of these people are involved in the fighting and dying, the conflict pushes more and more into the religious side.
It is even still an undercurrent in Northern Ireland after such a long campaign of killing on all sides and a peace agreement.
Religion is and always will be used/abused to further other aims as it is so powerful a tool to control and direct large groups of people.
It acts on the emotions more than the head and even moderate people can be encouraged to do terrible acts in the name of God. (Whichever God that may be)
I do not care if people wish to follow a religion, it is your choice and I once did, but I hold no illusions of what those people may do in its name if the right buttons are pushed.