Layla - sneaking up on people to do harm absolutely shows cowardice.  Attacking children shows cowardice.  Attacking unarmed people shows cowardice.  Running people down from the safety of a vehicle is cowardly.  Planting a bomb in the middle of a city that is unaware is cowardly.
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The lack of regard for consequences is not a sign of bravery but of a substandard ability to understand the consequences of ones actions.  In the case of Islamic terrorists they see the consequences as martyrdom and paradise ... hardly something to fear.