As you also see in the wiki article (I admit, I did not click the link - though I have read the page at some point in the past), there's an element of "Chaos Theory" involved.
You can really say Murphy's Law is Chaos Theory humanized, or some such statement of similar nature.
Honestly, if you does not accept Chaos Theory - then I have no further comments to make that will sway your opinion.
A simplified Murphy's Law makes it sound as if anything that can go wrong, will go wrong, every single time. That's the problem with taking old concepts and turning them into "laws", as well as the issue of paraphrasing and limitations of language.
It's not a guarantee that something you see that can go "wrong" (a subjective statement, in any shape or form - somebody's wrong might be a "right" - think of war, a bad stroke of luck for you can be a positive turn of events for your enemy) - it's merely a summation that such "wrong," when given a similar set of circumstances, at some point will most likely occur.
Which is simply an element of Chaos Theory, focused in a way that pertains mainly to humans and our limited perception; Chaos Theory, in short, dictates that anything that can happen, will happen, given enough time and chance. The Butterfly Effect will also be involved, as a small random event can cause an unpredictable but possible event to occur a vast distance away, or in the same region a great length of time post-event.
That's going off the deep end, when speaking of Murphy's Law - but your argument revolves around a [too] literal interpretation.
I thought of that old adage, mainly as it pertains to military planning/strategy: both Murphy's Law and "throwing plans out the window when boots hit the ground" both come heavily into play.
