As for bombs pushing people towards radicalism I think despair pushes people to brutal organizations like ISIS, and civilian casualties certainly contribute to that. Don't forget that to people suffering from such casualties those bombs have the names of taxpayers from Dallas, Texas and other cities on them. I do imahine we'd that the oppressive regimes many in the Middle East live under contribute towards rises of terrorist activity.
Oppressive regimes? Yes of course. Bin Laden launched 9/11 because he could neither get a rise out of the US via targets in Kenya or Yemen, nor was there a clear battlefield elsewhere in a Middle East which was then dominated by a chain of stable dictatorships. Now the whole region is up for grabs in a thirty years war. There's no reason to bring the fight to America when there's so much fun to be had in your own backyard.
But bombs? No. Not important.
