Acting as Captain Buzzkill, I feel obliged to point out that machetes were used to great effect in killing people in the Rwandan... civil war of 1994. A sharp metal edge is certainly not weaker than human flesh.
I like blunt objects, but I'll use a sword-like weapon if I have one.
Yes, but we were (or at least I was) talking about killing zombies, not (often sleeping) women, children, and unarmed commuters packed into trains. To kill a (Romero-type) zombie with a machete, you would either have to penetrate its skull and drive the blade deeply into the brain (in which case extracting the blade could be a problem) or lop off its head entirely (risking toxic exposure to large amounts of reanimate spooge). I don't think the Rwanda analogy is entirely apt. And, yes, I am over-using parentheses.