There are two kinds of media organizations (to paraphrase Clint Eastwood——from The Good, The Bad, And The Ugly, not from his recent muddleheaded drivel in support of Mr. Fuck-The-47%): those that are funded entirely by users' contributions and purchases, and those that sell users and space to advertisers or solicit corporate or government grants. For reasons whose soundness seems undisputed, Z has chosen to remain in the former category.
Although I enjoy the benefits that come with being a Sustainer, these benefits were not my main motive in becoming a Sustainer. Rather, I donate to Z because of my strong conviction that alternative media organizations like Z have social worth and value.
I would expect all who share this conviction to be similarly resolved to donate to Z; yet the opposite appears to be the case. For, the only way for a person to be constantly "badgered" by Z's persistent "irritating" requests for money is for that person to be constantly going to Z's website. But why go to the website unless it has material and information of social and intellectual value?