And if you don’t watch often enough for ad-free viewing to be worth a few bucks a month to you, then why get so worked up about having to sit through an ad every now and then?

There is an awkward gap where most services (not just YouTube) don't offer reasonable pricing for consuming small amounts of content. So if you consume a lot of YouTube, the subscription price is justified. If you consume very little YouTube, you can probably suffer through some ads. But if you're somewhere in the middle, there isn't a great option.

YouTube probably makes fractions of a cent off of ads on a single video it shows me, but I can't pay fractions of a cent to watch one video.

I'd consider this to actually be a pretty widespread problem across the internet, where it's frustratingly difficult to buy small amounts of content for a reasonable price. It's either the subscription or nothing for a ton of services.