the GDPR does apply to a camera in a bar. As long as it is used exclusively for security and data purged regularly, it can be claimed to be required.

Certainly the bar owner cannot distribute the videos without explicit consent. And yes, that can be problematic in many cases (for examples, capturing faces of people in a concert).

GDPR definitely applies to cameras in bars or shopping centers - in fact, much more of GDPR enforcement has been about issues such as those, the web world is not that important.

If a shopping center would want to distribute surveillance camera data to 'trusted partners' for marketing research without informed consent of the customers, that would definitely be a GDPR violation, and there would not be a "if you don't like it then don't go to that supermarket" situation but "if your supermarket can't survive without that income, then tough luck".

> Users have a choice to use the website.

Correct, and thankfully website operators don't get the choice to violate users privacy without consent.

The harm that can and most likely will be done by under-regulated trade of peoples intimate information is far greater than the harm of showing them ads. Targeted disinformation has already made a huge mess of US politics. Turning "personal computers", phones, and IoT junk into surveillance devices a la 1984 was either profoundly short-sighted and stupid or a very clever attack on individual liberty and agency, depending on intent of each actor involved. To the extent that knowledge is power, people are being tricked into giving up far too much. I say tricked because of what isn't immediately obvious when transacting with some tracking system on an otherwise free website:

When you give up a small piece of seemingly insignificant data about yourself a million times per year, the aggregate is wildly more significant than the sum of those pieces. When you and everyone you know give up the aggregate of each persons aggregate information, again, its value is compounded. Finally, since no one has any insight into nor control over where their data ends up or how it's used down the road, the danger of sharing is even less evident.

Good can and does come from transparency, but this is one-way transparency. It's top-down and is begging for abuse. If we had a truly voter-representative government, it would have already created laws to mitigate the easy-to-anticipate problems that arise from massive accumulations of personal information, and we would no doubt have a better, if less profitable, WWW as a result.