Is that wasteful? Does that make me a poor Internet citizen?

I personally don't think it's a problem. As I said, "a very popular site with that many millions of visitors already has to handle extreme traffic, regardless of RSS."

I'd never considered using RSS feeds from an app and pulling it directly. I have too many devices for that to be a great workflow.

A lot of apps have sync to handle that workflow.

my gut feeling on this is that the people still using RSS and people self-hosting would overlap in a big way.

My gut feeling is that most RSS users, including myself, simply use client apps.