In general I'm very sympathetic to this point of view, and there are some good examples in your post.
One bad example, in my opinion, is Eliezer's recent procrastination post vs. the survey of "scientific research on procrastination." I read the chapter, and it appears to mostly cite studies that involved casual surveys, subjective description, and fuzzy labeling. Although there are many valid scientific endeavors that involve nothing but categorization (it is interesting to know how many species of tree frog there are and what they look and sound like even if we do not make any predictions beyond what is observed), categorization should at least be rigorous enough that we can specify what we expect to see with a modicum of precision.
When a biologist says that frogus neonblueicus has neon blue spots and chirps at 500 Hz, she will give you enough information that you can go to Costa Rica and check for yourself whether you have found one of the rare neonblueicus specimens. Although there will be some controversies around the edges, your identification of any particular frog will not correlate with your political biases or personal problems, and repeated observation of the same frog population by a few different researchers will tend to decrease error.
When a psychologist says that procrastinators can be divided into "relaxed" types and "tense-afraid" types, the "science" being done is not merely descriptive, but also horrifyingly vague. What does it mean for a human to be "tense-afraid" when "procrastinating"? The three paragraphs or so of context on the topic give you enough of an idea of what the researcher is saying to conjure up a mental image, but not nearly enough to carve thing-space at the joints.
In my experience, this is a very serious problem in social and human sciences -- there are whole subfields where the authors do not know how little they know, and proceed to wax eloquently about all of the empty concepts they have coined. There are other subfields where the researchers suspect that they might not have done very good research, and they cover their tracks with advanced statistics and jargon. After you dig through a few of these booby-trapped caves of wonder, you start to lose, if not respect for scholarship, at least some of the urge to do the moderately hard work of digesting literature reviews yourself on a regular basis. It is dangerous to assume that casually studying the leading textbook in a soft field will usually make you smarter.
Perhaps my choosing a recent Eliezer article as one example of an underuse of schholarship is an instance of "people trying to show off how willing they are to disagree with" Eliezer Yudkowsky!
Eliezer Yudkowsky identifies scholarship as one of the Twelve Virtues of Rationality:
I think he's right, and I think scholarship doesn't get enough praise - even on Less Wrong, where it is regularly encouraged.
First, consider the evangelical atheist community to which I belong. There is a tendency for lay atheists to write "refutations" of theism without first doing a modicum of research on the current state of the arguments. This can get atheists into trouble when they go toe-to-toe with a theist who did do his homework. I'll share two examples:
The lesson I take from these and a hundred other examples is to employ the rationality virtue of scholarship. Stand on the shoulders of giants. We don't each need to cut our own path into a subject right from the point of near-total ignorance. That's silly. Just catch the bus on the road of knowledge paved by hundreds of diligent workers before you, and get off somewhere near where the road finally fades into fresh jungle. Study enough to have a view of the current state of the debate so you don't waste your time on paths that have already dead-ended, or on arguments that have already been refuted. Catch up before you speak up.
This is why, in more than 1000 posts on my own blog, I've said almost nothing that is original. Most of my posts instead summarize what other experts have said, in an effort to bring myself and my readers up to the level of the current debate on a subject before we try to make new contributions to it.
The Less Wrong community is a particularly smart and well-read bunch, but of course it doesn't always embrace the virtue of scholarship.
Consider the field of formal epistemology, an entire branch of philosophy devoted to (1) mathematically formalizing concepts related to induction, belief, choice, and action, and (2) arguing about the foundations of probability, statistics, game theory, decision theory, and algorithmic learning theory. These are central discussion topics at Less Wrong, and yet my own experience suggests that most Less Wrong readers have never heard of the entire field, let alone read any works by formal epistemologists, such as In Defense of Objective Bayesianism by Jon Williamson or Bayesian Epistemology by Luc Bovens and Stephan Hartmann.
Or, consider a recent post by Yudkowsky: Working hurts less than procrastinating, we fear the twinge of starting. The post attempts to make progress against procrastination by practicing single-subject phenomenology, rather than by first catching up with a quick summary of scientific research on procrastination. The post's approach to the problem looks inefficient to me. It's not standing on the shoulders of giants.
This post probably looks harsher than I mean it to be. After all, Less Wrong is pretty damn good at scholarship compared to most communities. But I think it could be better.
Here's my suggestion. Every time you're tempted to tackle a serious question in a subject on which you're not already an expert, ask yourself: "Whose giant shoulders can I stand on, here?"
Usually, you can answer the question by doing the following:
There are so many resources for learning available today, the virtue of scholarship has never in human history been so easy to practice.