Here's how I rank SECDEFs in terms of the worst:
1) Louis Johnson (Truman, 1949-1950): Main qualification for the job: he contributed $4 million (in 1948 money) to Truman's campaign. Cut the Army and Marine Corps to the bone, cut Naval Aviation, and sided with the USAF in the B-36 v. Carrier controversy, which provoked "The Admrials' Revolt." His cuts left the military unprepared for conventional war, and after the initial failures in Korea, was told by Truman to either quit or be fired. He quit, and there was cheering on troopships headed to Korea when that was announced.
To be fair, losing the
United States led to the Navy getting the
Forrestals by and by, and those were much better carriers due to incorporating post-
United States developments in carrier design and having a rather larger air group (if Wikipedia can be believed) despite being of similar size. I also have to point out that if putting Polarises on surface ships is a bad job, putting bombers on carriers is worse. Not only due you stand the risk of them getting sunk before they can do anything, but even when they do get their bombers off the bombers run a significant risk of being shot down before they can deliver their payload, which is probably half the reason (despite carrier aviation still being powerful in the Navy) the Navy's strategic nukes are underwater instead of in the air.
I also have to slightly defend McNamara in terms of space projects. I know it's practically heresy to say this, but him killing the X-20 and Blue Gemini was probably a good thing. Blue Gemini in particular offered very little to the Air Force, but even the X-20 was of questionable value (as was seen later with the much more capable Shuttle).
Now, if I were choosing bad SecDefs, I'd mostly agree with your list but add on Cheney, due to his unreasonable cuts in the early 1990s. In particular, as I've mentioned elsewhere, cutting the A-12 (which was reasonable) without providing funding for development of a true replacement project, either the A-6F or the various Tomcat upgrade proposals Grumman put forth. Or did you stick him in #5 and just not go that far?