You appear to be putting words into my mouth, but I'm currently too irritated to detangle this much beyond that point.

"Giving people too much credit" was a reference to peoples' desire to be rational. I tend to assume that that's significantly above zero in every case, even though the evidence does not seem to support that assumption. This is a failure to be rational on my part. (I doubt I'll fix that; it's the basis for most of my faith in humanity.)

I make no such assumption about intelligence (I do not assume that people want to be more intelligent than they are), and make a conscious effort to remove irrational biases toward intelligent people from my thought process when I encounter them. I have been doing so for years, with a significant degree of success, especially considering that I was significantly prejudiced against less intelligent people, before I realized that it was wrong to hold that view.

I have also put significant effort into learning how to bridge both of those communication gaps, and the skills required in each case are different. When I'm simply dealing with someone who's less intelligent, I moderate my vocabulary, use lots of supporting social signaling, make smaller leaps of logic, and request feedback frequently to make sure I haven't lost them. (Those skills are just as useful in regular conversation as they are in explaining things.) When I'm dealing with someone who's not practicing rationality, I have to be very aware of their particular worldview, and only thoughtfully challenge it - which requires lots of complicated forethought, and can require outright lies.

The lack of either of those sets of communication skills will make dealing with the relevant people difficult, and can lead to them thinking poorly of you, whether you actually are prejudiced against them or not. Assuming that someone who does not have one of those sets of skills is prejudiced does not, in practice, work - there's a very high risk of getting a false-positive.

Is it impossible to be an x-rationalist and still value people?

This is something I’ve thought a lot about. I’m worried about the consequences of certain negative ideologies present here on Less Wrong, but, actually, I feel that x-rationality, combined with greater self-awareness, would be the best weapon against them. X-rationality -- identifying facts that are true and strategies that work -- is inherently neutral. The way you interpret those facts (and what you use your strategies for) is the result of your other values.

Consider, to begin with, the tautology that 99.7% of the population is less intelligent than 0.3% of the population, by some well-defined, arbitrary metric of intelligence. Suppose also, that someone determined they were in the top 0.3%. They could feel any number of ways about this fact: completely neutral, for example, or loftily superior, or weightily responsible. Seen in this way, feeling contempt for "less intelligent" people is clearly the result of a worldview biased in some negative way.

Generally, humanity is so complex that however anyone feels about humanity says more about them than it does about humanity. Various forces (skepticism and despair; humanism and a sense of purpose) have been vying throughout history: rationality isn’t going to settle it now. We need to pick our side and move on … and notice which sides other people have picked when we evaluate their POV.

I always find it ironic, when 'rationalists' are especially misanthropic here on Less Wrong, that Eliezer wants to develop a friendly AI. Implicit with this goal -- built right in -- is the awareness that rationality alone would not induce the machine to be friendly. So why would we expect that a single-minded pursuit of rationality would not leave us vulnerable to misanthropic forces? Just as we would build friendliness into a perfectly logical, intelligent machine; we must build friendliness into our ideology before we let go of “intuition” and other irrational ways we have of “feeling” what is right, because they contain our humanism, which is outside rationality.

We do not want to be completely rational because being rational is neutral. Being more neutral without perfect rationality would leave us vulnerable to negative forces, and, anyway, we want to be a positive force.

It may come as a shock, but in my case, being rational is not my highest priority. I haven't actually come up with a proper wording for my highest priority yet, but one of my major goals in pursuing that priority is to facilitate a universal ability for people to pursue their own goals (with the normal caveats about not harming or overly interfering with other people, of course). One of the primary reasons I pursue rationality is to support that goal.

Once I realized that achieving anything, no matter what, required my being rational, I quickly bumped "being rational" to the top of my to-do list.

Is it impossible to be an x-rationalist and still value people?

'People' do not lend themselves to any particular utility. The Master of the Way treats people as straw dogs.

If we assume he has goals other than simply being a self-abasing misanthrope, the attitude Annoyance is showing is far from rational. Arbitrarily defining the vast majority of humans as useless "problems" is, ironically, itself a useless and problematic belief, and it represents an even more fundamental failure than being Spocklike -- Spock, at least, does not repeatedly shoot himself in the foot and then seek to blame anything but himself.

I don't want to catch flies.