Why do sites warn about the use of cookies?

Question

HTTP Cookies

Especially on the sites of large offices - a half-screen banner about "you agree to the use of cookies and blah blah blah." It is clear that sites use everything they can and collect the maximum amount of information, so why these annoying banners? Someone (something) obliges them [site owners] to do this or is it a type of image element, they say, "we care about you, but we will leave a couple of cookies and now you know it"?

Answer 1

The EU cookie law came into force in 2011, but the ICO (Information Commissioner's Office) decided it was only fair to give site owners one year to comply with the law. The deadline was May 26, 2012. From that date, sites that do not comply with the law can be fined £500,000.
In general terms, the new rules require a website to obtain permission from visitors before placing cookies on their computers. This means that you should directly ask visitors if cookies can be stored and clearly explain which cookies are used for what.

https://habrahabr.ru/post/143235/

Answer 2

Proof?