it's slightly vague but bear with me ...
well, no, if it's vague, it's not really a prophecy, now is it? Unless you are telling me that prophecy is vague, so vague as to mean any number of things, in which case it's just people saying vague stuff.
Now to you it's tenuous/nonsense, to me it's tenuous/nonsense, but there are plenty of Christians who sincerely believe this crap.
John Hagee is a modern prophet, using vague language in the Bible to declare God saw this coming, whatever the "this" is.
Point is, lots of people believe lots of things. A "prophecy" that can apply to a hundred things and only after the fact sort of can mean what you want it to is useless. Is that how we are defining prophecy? If so, yes, it's a prophecy.
If, however, we are defining it as "a foretelling of future events", it's kind of important to have, you know, actually foretold the events.
They believe that one of the twelve would betray their master, not because nasty God forced him to but because this particular apostle chose to do so - exercising free will, tempted by the money.
Well, that's another conversation, but it's impossible to have both free will and an omniscient god that knows the future.