I'll give my worthless 2 cents on the topic.
First, I agree the statement you quoted is crap. My playing buddy and I are what I would consider "competent" and we almost never skulk and are pretty evenly matched when it comes to wins.
In our games I've used it a few times, and I think it's sort of a standing, unofficial rule that we just don't rely on that crutch. Now if I were to play in a tournament and a setting where it's being used by everyone else...then I would probably use it too. Like the IIFT.
I certainly don't think it's necessary to win like that guy believes.
I know skulking is a result of the mechanics of the rules, but I don't believe it's in the spirit of the rules...or the tactical combat the rules are supposed to simulate.
I think a better implementation (and I'm pulling this out of my ass) would be some sort of movement mechanic like "going to ground" where a unit declares "GTG" at the start of their MPh (costing all MF) and are marked with a counter. This gives them a temporary psuedo-TI type status, all fire on them is area fire, they can't move obviously, it doesn't allow them to fire during the AFPh, and doesn't allow them to advance...but they can still be fired on instead of artificially hiding from LOS temporarily. After the APh the "GTG" counter is removed.
I think something like this is more realistic. Soldiers would seek extra cover to hold a position, forfeiting movement and the ability to fire effectively, but allows them to hold positions they want to hold. Soldiers wouldn't step out of the back of the building, have a smoke, wait 5 minutes, then go back in the building.
Again, I'm just spit balling here.
Bottomline, skulking is legal within the mechanics of the rules, but I think it's cheeseball mechanic if used excessively.
That was too long.