Defending Apple's business decision as if it were really a means to protect the user from harm is rather silly. It took a while for Apple to allow effective ad blockers on iOS, was that meant to protect users as well?
As said, I never have (nor had) problems with notification spam for the simple reason that only allow notifications for sites which need it. I don't have problems with spam because I block the stuff, I hardly see any advertising as I block that as well.
Communications is an adversarial field, there are those out there who'll try to get their message across by any means. Whatever way you choose to limit their access to your eyes and ears (and other sensory organs, and eventually your brain), there will be trade-offs. As an example I choose not to have a television in my house as that medium has been entirely taken over by adversarial parties. I do have computers of all sorts which connect to the 'net even though those are also being targeted by those parties. In contrast to television the computers give me the means to tailor the communications to (what I perceive to be) my wants and needs without needing to allow too many other parties access to my time and attention.