Islamic terrorist attack, or just 2 crazy people decapitating another person?

I'm unsure of what constitutes a Terrorist attack but I know that 2 Islamic people (followers of the religion of Islam/peace, to hell as like), the reason why I have put that is one because they were Islamic and two they were shouting Allahu Akbar (or in Arabic: الله أكبر).

which is an Islamic phrase called a Takbir in Arabic, which means "God is greater" or "God is [the] greatest" but I can honestly say that your God is not great if it got you to decapitate that man, it actually shows me how powerless it must be if your God couldn't do it it's self and just prove it's own existence to all of us instead of getting these two obviously mentally deranged people to act out doing crazy stuff, but then that's the problem with these god concepts they all are just ideas written many thousands of years ago and they have had all of that time to get themselves entrenched within human culture just so now if someone picks up a bible or a Quran they can read into it what they personally want to do and just cherry pick out the stuff that they want and they could leave the rest on the shelf.

So how powerless would a god get if he had to get two practically insane to kill one man? Surely if it was an all-powerful entity as your "holy" books indicate why doesn't bit just evacuate the O2 content from within his blood instead of getting some crazed lunatics to do such an act? How weak must your god be if he's only picking the insane to do acts off such barbarity if it was 

the same god that you worship?

All I could say is that for all of my faults I am more worthy of your allegiance than any of the so called Gods, and I most probably won't request it.

As if by magic i have got the definition of what a terrorist attack is for you at the bottom of this page...

Noun

1.

terrorist attack - a surprise attack involving the deliberate use of violence against civilians in the hope of attaining political or religious aims act of terrorism, terrorism, terrorist act - the calculated use of violence (or the threat of violence) against civilians in order to attain goals that are political or religious or ideological in nature; this is done through intimidation or coercion or instilling fear