While I do understand your take, I'm not sure it's a net positive for consumers. Marketing to previous customers is a very effective marketing strategy. If you prevent that, small companies are losing one of the few ways they can compete with bigger operations. Otherwise they have to keep buying ads on Google and Amazon..

Yes, most mail from retailers is spam. But for a handful of small retailers I actually like their newsletters, because they remind me that they exist, so I remember them next time I order something.