After further dinking around with uBlock Origin, it looks like disabling cosmetic filtering on the site (the third button from the left on the bottom), rather than disabling javascript, gets rid of the blegging dialog without disabling YouTube videos.
Like others, I would probably be willing to pay a subscription fee for an ad-free BoingBoing. Having to pay a per-page rate via Google Contributor (whoever heard of Google Contributor before today?), on the other hand, will just encourage people to find a way around it.
