Thanks, Ben. I agree with about half of the points and disagree with the other half. I think some of the claims, e.g., that other people haven't raised these issues, are untrue.

Effective altruists often express surprise that the idea of effective altruism only came about so recently. [...] But no one seems to be actually worried about this—just smug that they’ve figured out something that no one else had.

Honestly, I think this idea is one of EA's bigger oversights -- not that people haven't noticed that EA is recent, but that people don't realize that it's not recent. The components of EA have each existed for millennia, and movements combining several parts are also ancient. This particular combination may be a little different from past movements, but not more than past movements have been from each other.

On the whole, I think EAs vastly overestimate their value relative to everyone else in the world who are actually doing some really important work as well but don't happen to be part of our social circles. I agree that EAs (myself included) would do well to explore more different perspectives on the world beyond the boundaries of their community.