It is not a cookie-warning, it is a tracking-warning.

It is not a question of cookies per se. You can use localStorage and other techniques to track users without using cookies. But you still have to show the warning if you are tracking.

And there a plenty of legitimate uses of cookies.

There are plenty of use-cases that are covered by implicit consent where the website uses cookies for basic functionality (like login sessions or shopping carts) where no banner is required.

Its worse than that. I used to use a cookie whitelist addon in firefox, so only a few sites could set cookies at all.

I stopped using it because if you blocked websites from setting cookies, that meant the cookie consent banner showed on every page rather than the first you viewed because the cookie consent cookie had been blocked. That made blocking cookies entirely apart from whitelisted sites impossible.

If those scum-of-the-earth add tech companies would have respected the DO NOT TRACK flag, I'd concede that you have a point.

Wanting to limit what kind of cookie is the purpose of the law. I want some cookies (like user preferences, session tokens) but not the one from advertisers to follow me across domain names.

Not every one is tech-savvy and that is why we have regulations.