> If by "business model" you mean, "how do we keep the lights going", that's fair.
That was roughly my read. While "business" is frequently used as a synonym for "for profit company", that's not the only definition. Someone saying "that's none of your business" is unlikely to be talking about S corps.
> However, that's not the primary mission of Let's Encrypt.
It's the means by which they accomplish their primary mission. Can't encrypt the world if you can't keep your servers on.