To be honest, I don't think that your average Sith *gets* intelligence. My SW, anyway, really saw any good foe as one she could clobber with a lightsaber. She wasn't very smart. She wasn't particularly clever. She saw something's physical (and Force) strength as it's greatest determinant of value. (This bit is hinted at when you're told that the Sith and Jedi aren't paying attention to the Star Cabal because they don't care about almost anything that's non-Force related. They're like little demi-gods, playing games with their magic powers, unaware that there's stuff out there that may be even more powerful than their magic pixie dust.)
Intelligence is the complete opposite of the Sith. It doesn't value magic; it values technology. It doesn't value brute strength; it values cunning.
Is it any surprise that the Sith don't know what to do with it other than strip it of its assets? Not really. From everything we see in the game, neither the Jedi nor the Sith are overly crafty. They're just a bunch of kids with super powers. That's the whole *point* of agent - that giving a bunch of ordinary humans super powers and letting them do whatever they want is a horrible, terrible thing for the 99% of people in the universe who don't happen to have those super powers.
This, so much. The Sith value Strength(tm). If a given Sith ceases to be Strong, his apprentice kills him and takes his place. This might keep them sharp (and good at spotting plots, stupid isn't quite the right word), but in the end the characteristic that is selected for in the ranks of the Sith is being really good at killing other Sith. Furthermore, they value Passion. One of the roads to increasing your power in the dark side is increasing your Passion, and letting your emotions give you strength.
Being THE VERY MOST PASSIONATE and THE STRONGEST... actually they're kind of like Evil Kamina. But regardless! It doesn't lend itself well to being tactical and "thinky." It lends itself well to being PASSIONATE and STRONG and to thinking of other Sith as your biggest enemies. (NOT the Republic.) So yes, they'll do completely braindead things like disbanding Imperial Intelligence because they aren't on the Dark Council for their strategic acumen. I was pretty annoyed by it at first, but as I thought about it and played through other storylines (and got to see the Council members who weren't Jadus) it started to be exactly consistent with what I knew of the Dark Council.
Maybe you hadn't noticed during the other chapters of the Agent story (they don't really go out of their way to rub your nose in it), but the biggest thing holding the Empire back is the Sith. Not because they're stupid necessarily, but because they have massive cultural and systemic biases that the likes of the Cabal can use against them. Most of them probably think of Imperial Intelligence the way you think of your garbageman - and of course you can fire him with no ill effects if he's causing trouble, right? They have holes in their viewpoint that you can drive a truck through.
Jadus is relatively unique among his peers. Codex describes him as cold, seething, and brilliant. Of all the plots by Sith in the game, his probably is the best, because he's the one who gets it
The only other Sith in the KotOR series who come close are Darths Traya and Revan.