From your link:
"Those most lacking in knowledge and skills are least able to appreciate that lack....The Dunning-Kruger effect requires a minimal degree of knowledge and experience in the area about which you are ignorant (and ignorant of your ignorance)."

First off, can't we assume that most everyone on this forum does actually know something about philosophy? That members have more than a minimal degree of kn. and experience? Maybe not about every single topic that arises, but we are all familiar with the discursive specificities of philosophy.

Many of us are definitely under the impression that we're smarter than we actually are and an interesting question would be to ask how and in what way it's an impediment to true knowledge. — TheMadFool

My view on this: the real issue is denial. If someone's in denial about how much intelligence s/he possesses, that's a psychological impediment preventing the subject from knowing her/himself realistically, without having to distort self-image.

You're right.

Everyone always forgets about the other half of Dunning-Kruger: people who truly know a significant amount about something, enough to know how much they don’t know, tend to think lowly of their knowledge, even though it’s much greater than others. (See also the legend of Socrates and the Oracle of Delphi).

I sometimes find myself wondering about the reflexivity of Dunning-Kruger. If it seems to me that I know a lot about things, and I know about Dunning-Kruger, and so conclude that I probably don’t actually know very much at all, does Dunning-Kruger then suggest that I probably do actually know more than, due to Dunning-Kruger, I think I do? Or conversely if I am well aware of the vast sea of knowledge I’ve yet wade more than knee deep in, but knowing about Dunning-Kruger, I therefore conclude that I probably know more than most people, does Dunning-Kruger then suggest that I probably know less than I, due to Dunning-Kruger, think I do?

Or what about jacks of all trades? My general impression of my own abilities is that, for most X, I am better than most people, but worst than most Xers, at Xing, such that most people think I’m an expert on most things except the thing they’re an expert on. What does Dunning-Kruger say about that?

Knowledge is inexhaustible, it makes sense that someone who therefore holds a lot of knowledge would be aware of the difference in ratio. Not to say that this is an absolute though

Everyone always forgets about the other half of Dunning-Kruger: people who truly know a significant amount about something, enough to know how much they don’t know, tend to think lowly of their knowledge, even though it’s much greater than others. — Pfhorrest

Perhaps I am wrong, but it seems to me truly intelligent people know they are smart and know they are smart than most other people, but this isn't their focus when engaged with learning, problem solving. Their focus is on what they do not know and what they need to know. When waxing comparative, it would be odd for them not to realize they are much smarter than most other people.

And let's look at the actual context of the research: they tested people new to a field. People studying psychology for the first time. The smart students were focuses forward and what they didn't know. Because that's how one learns best. One enjoys challenges and focuses on them and this was early stages in a subject area. They have reached a place, where a psychologist is, where they can now consider themselves experts, they are just getting their feet wet. The poor students are focused on what little the learned, not on challenging themselves, not on the future. Poor students do not dive toward self-challenge and do not focus on what they don't know (yet).

There has also been follow up research on this effect and it concludes....

The authors' findings refute the claim that people are generally prone to greatly inflated views of their abilities, but support two other tenets of the original Kruger and Dunning research: (1) that self-assessment skill can be learned, and (2) that experts usually self-assess more accurately than do novices. The researchers noted that metacognitive self-assessment skill is of great value, and that it can be taught together with disciplinary content in college courses.[16][17]