icarus5 - even the discovery documentaries about this crash show enough details to show what happened with respect to the strip found. The form and shape of the titanium strip found match exactly the tyre cut pattern on the burst tyre for a very large 70lb chunk of rubber that also matched the indentation on the wing.. They put the strip up against the rubber and it followed it exactly. That evidence is pretty clear in that regard.
This was not normal FOD - it was a roughly cut, jagged extremely stiff chunk of titanium instead of a properly manufactured aluminium strip. It was sharp and hard enough to slice a pretty substantial aircraft tyre on contact, where as the specification strip would have been crushed by the tyre.
Like any disaster, there is more than one aspect that contributes to the end result, but this strip is a major factor and in my view the critical one. Dismissing it and the raft of physical evidence relating to it is not rational. The legal and blame games are another matter, but don't just dismiss a critical fact because it disagrees with a jingoistic view of the matter.