I think for starters you have to break it down into subcategories. Weather, aerobatics etc.
I disagree -- it all falls under the concept of "airmanship". We are talking about decisionmaking and judgment. We are talking about flight discipline.
Unfortunately, this is a topic that non-professional aviation has to struggle with every handful of years; most professional aviation has a set of standards and expectations that come with the job that -- generally -- are followed lest the pilots lose that job. Unfortunately, in
non-professional aviation (e.g. GA flying, amongst other areas), we come from varied backgrounds, with varied levels of training, varied levels of experience, and varied beliefs about levels of what constitutes safe behavior in an airplane. Because of those variations, it is nearly impossible to have a single, understood standard/example of what "normal" behavior is, especially as pilots progress into flying more and more high performance airplanes that are capable of more high performance things.
The warbird community has struggled with this over the years, especially as the "old guard" of former professional military pilots who were the standard-bearers in the warbird community has died off and been replaced by a large number of non-professional pilots whose actual professions afforded them the wealth to own/operate high performance airplanes. Pilots who have not been trained formally or mentored by pilots with experience high performance flying (the same stuff mentioned in the article -- formation, aerobatics, low-level flying) unfortunately sometimes make the decision to have a go at it themselves. Or, alternately, they've been trained and mentored on how to do this stuff, and they still make the decision to engage in risky or illegal behavior anyway because of the laundry list of "hazardous attitudes". There was a point about 5-6 years ago where every single fatal warbird accident that year was a result of pilot error, and most of it from guys saying "watch this!" and doing things that were far riskier than circumstances dictated or were above their heads trying to do something their training or experience could not support. The warbird community continues to struggle with this today, even having self-identified the issue and having taken steps to tighten up their own training and self-enforcement of good decisionmaking.
Either way, it constitutes bad decisionmaking, bad judgment, bad airmanship. Some (most?) pilots strive to learn and achieve excellence in these areas...but some don't. Some just want to go have a thrill, and think that they're good enough to make it work without killing or injuring themselves or others.
In my opinion, if your take-away from the article is that the author is unfairly pointing a finger at RV pilots, then you've gleaned entirely the wrong thing from it. Such an article should, instead, cause us to look at ourselves and our fellow pilots, and examine if we have those same thoughts and behaviors. He's right that no pilot thinks of himself as dangerous, and none of us wake up in the morning and think, "hey, let's go out and do something stupid today!" Often we can't see it from inside the fishbowl -- sometimes it takes us stepping back and examining things from the outside to see these things. Sometimes it takes a friend, a fellow pilot, a mentor, or even a stranger to comment on what they think of your airmanship and judgment for us to realize that we may be slightly off the ranch.
It has to start with each of us wanting to be good airmen and both learning and exhibiting good judgment and decisionmaking. It extends to when we see bad judgment or poor airmanship out of fellow pilots, having the guts to go speak to them about it.