I got the 75 number from Doug Wead, it's not some emotional, knee-jerk reaction to Rand Paul.
Doug Wead, as in, not Rand Paul? Regardless, you still brought Rand up out of the blue to bash him.
I oppose the foreign policy because it is immoral, not because it is too big or inefficient.
Holy crap, you do? You oppose empire because it's immoral? You must be the only one on the forum! Now I totally understand, because I cannot POSSIBLY imagine someone who opposes an imperial foreign policy for moral reasons thinking that eliminating 90% of the bases in a fell swoop would help reduce current and future death and destruction.
The vast majority of people here oppose war and empire primarily for moral reasons. This includes not only hardcore libertarians - such as myself - but a whole boatload of anti-federalists, Constitutionalists, and even paleocons ("just war" theory and all that). Besides, the "too big" and "inefficient" aspects impact moral issues as well, because the way things are going, a petrodollar collapse might result in World War III. This is less likely now that we dodged a bullet (no Mitt Romney), but it could still happen, so cutting spending just might be the way to prevent a nuclear holocaust.
Starting at a position of keeping 75 bases open around the world would leave the worst bases open (hot-zone bases), and would assuredly lead to a final result of having many hundred more still in operation.
The first part is correct: The hot-zone bases would remain if we cut back to 75, because it's harder to convince people to close them. (It might be easier after the others are closed though, because, "See? The world didn't end.") That's no excuse not to take what we can get when we can get it: If someone thinks we can eliminate all but 75 immediately and you think we can eliminate all of them immediately, then great...but for Pete's sake, cut out the melodrama about anyone disagreeing with your analysis being the "end of the movement."
Doug Wead may believe that campaigning on cutting back to zero immediately would risk no cuts at all, due to voter rejection...and if he believes this, he might be right. If we cut down to 75, then 35, then 10, then zero, and we keep up the pressure, we're eventually going to get rid of all of them. The risk is that we might be shooting too low, in which case we could have gotten rid of all of them sooner before more people died.
I can understand the fear that if we aim to cut down to 75 in one step we'll only actually cut down to 200 in one step...but that is a practical matter, and there's a flip side to that coin: If we try for all of them at once, fail utterly, try again, fail utterly, and keep trying and failing utterly, then we will have gotten rid of none, and more people will keep being killed over and over and over due to our stubborn insistence on perfection in the face of pure evil. In the meantime, we might have made it to zero by then if we had taken another path. NONE of us no for sure where the optimal radicalism/gradualism balance is for getting to zero as quickly as possible: We all have our opinions, but no one knows for sure.
In short, radicalism vs. incrementalism/gradualism is not always a moral issue, at least with respect to the NAP. Most of the time, it is a strategic disagreement between people with similar or even identical morality trying to determine just how much violence and coercion they can eliminate in any given step. You implicitly conceded this the moment you supported Ron Paul, because even in 2008, he did not run on the platform of "abolish the state immediately."
I believe in shooting as high as reasonably possible, and I believe eliminating all the bases in a single term is reasonably possible given the right political circumstances...but if someone else genuinely believes otherwise, I'm not going to sit quietly while people crap all over him like he's some kind of poison pill. If someone else runs for President under a genuine platform of reining in the state as much as he thinks he can in every possible area (without expanding it anywhere), I'm sure as hell not going to say, "I'd go farther, so he's the death of the movement," and stand aside out of spite while he loses to Bomby McCrazy. THAT's the kind of attitude that could lead to the death of the movement.
Everyone has their litmus test, and I will not go out of my way to support anyone who would increase government in virtually any area, with case-by-case exceptions regarding the contentious abortion and border issues. The exceptions here introduce an element of risk, but practical concerns necessitate them, or I could have never supported anyone, including Ron Paul.

When it comes to voting alone, I'll vote for the best candidate available if there's a clear best...and abstain otherwise. Some lean more toward abstaining for reasons of moral responsibility, and I can respect that as long as they aren't too judgy toward others. Some people are willing to further compromise, which I do consider increasingly dangerous. For instance, I'm not convinced that Ted Cruz is an authentic liberty candidate or worth all the effort spent on him...but time will tell. Besides, many here are Constitutionalists anyway, and they abide by their own hard principles (though I'm not sure if Cruz meets that standard or not...). Some people outright refuse to support or vote for anyone unless they'd go "really far, really fast," which I kind of consider pointless and counterproductive when the choice is between someone who wants to incrementally reduce government in every area vs. someone who wants to increase it in some areas (or every area)...but to each their own. People can abstain if they want, when they want.
Nobody has to support anyone...that's not my concern. My concern is that the extreme judgmentalness toward anyone who isn't "radical enough" in terms of rhetoric or timescale is getting absolutely ludicrous. Murray Rothbard was a champion of radicalism...and yet even Murray Rothbard would be ASHAMED at how libertarians are behaving today. If you think a liberty candidate isn't radical enough, don't eat them alive and do everything you can to discourage people. Instead, prove you can do better.