Ask HN: Why don't they remove the cookies (and hence the banners)

I get it if you're an ads-driven website

But why do agencies, municipalities, (government) railways or other non-ads driven websites need to have cookies, and hence the frustrating banners?

My hypothesis is they want to be "better safe than sorry" but maybe there are real marketing purposes behind it?

some examples: https://www.mckinsey.com https://www.london.gov.uk https://www.ns.nl (Dutch railways) https://www.britishmuseum.org