SEO also has the purpose to rank your website high so that you can sell your products. A huge part of the internet has nothing to do with ads, but businesses selling their products and services

I think if they want to sell to me and ads&trackers harm their SEO, it'd at least make the internet a little bit more private.

That or it'll be a cat and mouse chase like cname cloaking/proxying rendering those harder to statically detect.

True for you, but there are billions of people out there and your attitude is a tiny minority for what they would lose elsewhere.

Boss of wonderful search site seems to be unaware?

Unlike Google who has incentives to promote the spam Kagi has incentives to fight the spam.

Also Kagi lets me blacklist domains myself if I want stricter rules than Kagi already provide.

The financial motive is to get people looking at your website so you can sell things. SEO has always been an arms race, and I don't see how it can not be that. Occasionally there's a paradigm shift that causes one side to get massively ahead (e.g. the original Pagerank). But eventually things settle back down.