I think it does a lot more than foreshadow Crusade. It gives you a good indication of whats going on back home... this together with Earth's active stance with the Deathwalker situation/Epsilon III and the hidden factions in the Government backing Home Guard and a few other things tell us that Earth has not come to terms with it's dismal performance in the Minbari War... and this has led to a dangerous obsession with alien tech... in a bid to develop shortcuts to be on an even keel with a race such as the Minbari once more.
There are lots of little touches (even with guest or minor characters) that give us an inkling that Earth is a place that has a lot of fear, self doubt and insecurity.
It's this fear that leaves them wide open to the approach of Morden... and leads to the xenophobic idiot Clarke, moving himself into a place where he can seize power.
This may have been the first episode to give us these clues, followed by many more. It became apparent fairly quickly that in this show, Earth wasn't the secure utopian hub of some enlightened Federation. Your analysis of Earth's political and social climate and why it probably developed is pretty spot-on. Maybe a bit like Germany after WWI, minus an analog of the Versailles Treaty, but instead, oddly, a "surrender" of the enemy that no one could understand--other than perhaps that some "fifth column" was in place, hence the suspicions about Sinclair, general xenophobia, etc. But it sort of echoed "stabbed in the back" sentiments among many Germans after WWI, leading to the horrible scapegoating of a certain "Other" within that society.... Indeed, the intent of that Ikarran technology dovetailed pretty well with that pevailing mood on Earth, although the Earthers probably didn't know what the B5 leaders learned about Ikarran history. They were, as you say, simply looking for any shortcut to military advantage--possible dangers and consequences, including those from not really understanding what they'd discovered, be damned.
This ep does have a good bit to offer beneath the surface, although I agree that much of the immediate story was executed rather hamhandedly, and probably doesn't impress on first viewing before knowing the arc Earth takes in the series. I think at first viewing I did pick up a little that something may not have been quite right with Earth, but probably chalked it down to "the military-industrial complex is still alive in this future". I don't think we even know yet the nature of the Earth-Minbari War and that we got our asses handed to us (unless this is mentioned in "the Gathering", but I didn't watch that--separate DVD--until after the series proper).
