I would argue that a little thicker skin is in order for both 'sides'.

I'm a relatively new woodworker, and haven't always known what I don't know. I've been corrected many times. While it smarts sometimes and hurts my ego every once in a while, the dialog left in its entirety (sans petulance and rudeness) is probably very useful to other newbies.

Similarly, I think the expert teachers also need some patience for we students. Discussions often devolve because the experts don't have patience for challenges or questions to their data or experience. Guys like David certainly owe us nothing to suffer these debates, but I humbly suggest that they'd do better to just disengage from individual threads instead of disengaging from the site as a whole.