Because it's not about cookies.

The law is explicitly about 3rd party cookies, something that is harder to classify.

The intent of the law was to get website owners to stop leaking data to 3rd parties.

The result was everyone slapping a poorly understood warning label on everything.

If you're taking about the EU "cookie law" then it is neither about cookies nor about third party data. The summary is you can store data if they support the primary function of your site without the popup. E.g. you have a shop so you can place a cookie to track the cart but not cookies related to tracking what your user looks at. Despite the name the law is generic about data stored on users computer so cookies, local storage, etags, all are covered by that.

because the law says so, and the law was written by bureaucrats with no understanding of the industry or of the extremely predictable outcomes of their legislation

They are it seems -

Cookie banner frustration to be tackled by EU

http://www.bbc.com/news/business-38583001

What do you mean by at the browser level? Should Chrome/IE/Safari 'know' the site uses cookies and show something in the browser as per the https padlock?

As an aside I do find it funny how 'bosses' insist on the cookie notice to make their website official looking.

> What do you mean by at the browser level? Should Chrome/IE/Safari 'know' the site uses cookies

Absolutely! How else does it know to store the cookie on the user's machine.

Storing cookies isn't the trigger for the warning; no notification is required for cookies that are essential for the basic navigation and operation of the website.

So how would the browser differentiate those cookies from ones which are being used for data collection and tracking, which do require the warning message? It would require some sort of intent-signalling protocol between the website and the browser, which is probably more complicated than just requiring the site operator to include a bit of HTML.

For practical purposes, you could approximate it based on whether the cookie is first-party or third-party and on the amount of time until the cookie's expiration. For the most part, first-party cookies with a short time to expiration are allowed without warning under the EU law, all other cookies require the warning.

Didn't IE or some other brower put a cookie in the address bar if cookies were used?