All domains need contact information. Otherwise it becomes impossible to perpetuate the healthy operation of the domain pool. Domains which do not have valid contact information are subject to be released back into the pool.
I don't care if you're being spammed. If you refuse or are not able to provide a valid means of contact you don't deserve to participate in the domain registration system.
As said several times already, NO ONE is saying that contact details cannot be asked for and stored, IF that is needed to provide the service. This is about who has access to that information. i.e. ICANN having access to your email/phone number in order to let you know your domain is about to expire is a valid business requirement, so is allowed, but some random person on the internet being able to grab your personal contact details in order to spam you is not!