I don't like cookies. My browser is set to discard them after it is closed. I have no problem with logging in every time I reopen the browser and want to use a Stack network in a non-read-only way and I fail to see why any of them would be "necessary".
Recently an enormous cookie banner was introduced in AskUbuntu. It takes about one third of the window until the user decides what to do about his cookies (and of course the shortest path is to accept all), partially obstructing the questions and answers, which are the very reason people visit this website.
The previous cookie consent banner was a decent footer that did not make it impossible to read posts. One could ignore its existence.
As far as I can remember, Stack has always had an uncluttered interface with sane and respectful choices. No gigantic banners. We know what the next step is: A large pop-up asking visitors to log-in or to create an account. Actually this is already a big header as you can see in the picture, but at least it goes away as one scrolls down.
The new banner harms the user experience. It is too big, too intrusive. I suggest the interface design team considers rolling back to the previous footer banner.
Note: A/B testing is ongoing, so the full page banner may be smaller for you (see comments to this related answer in Meta). Slightly better, but still intrusive.