So first of all, yes, it's kind of terrorism. But it's also good and necessary. He just had enough, but what is required are people not driven by impulsive emotions, but by planning. Also excellent weapon of choice. But what, he *tried* to kill 5 and didn't succeed? That's sad.
Second, you don't "stab" with a machete. While you can thrust, slash, cut, hack with a sword, with machetes you really just can hack. But they do that REALLY well, and the motion is essentially just a "beat it with a stick", and if done right, it can cut deep, separate limbs and heads. The damage depends on the strength and velocity used.