The unscrupulous advertising practices out there (e.g. straight-up malware deliver) make it too dangerous to not run ad-blockers. Until the security issues around advertising are addressed adequately, I consider blocking entirely ethical. Compare it to the idea of Target shaming users for not trusting them with their credit card info.

Besides, I expect direct patronage models to supplant advertising for smaller sites sooner rather than later. And yes, I already use Patreon.