That doesn’t matter in a world full of iframes, js sdks, app/site integrations, and shadow accounts. A company with the massive reach of Facebook or Google can absolutely track you all over the web without you ever signing up for or even directly using any of their services.

That doesn't stop facebook to track you

You can also make a voluntary decision not to buy products from a company that dumps toxic waste into the water supply -- does that mean they should be able to do it?

Just because you are not giving them money or you can choose to personally opt out does not mean they are not doing societal harm, and a democratic government has a mandate to minimize the harm done on society as deemed by its population.

Libertarian justifications are great thought-pieces, but ignoring the social contract is only awesome if you are rich and have no empathy.

Can you also make a voluntary decision not to file taxes?

https://www.cnn.com/2023/07/12/tech/tax-prep-companies-taxpa...

You can't opt out of certain surveillance, even by never touching the surveilling entity. But regulation can curb these practices, like how GDPR did.

https://en.wikipedia.org/wiki/Shadow_profile

You cannot opt out of their scumbag data harvesting practices though.