If I were to ask a question like that, would I be in on-topic territory?
Your original post is on topic and should have remained open. In fact, its wording makes more sense --and provides better context-- than the version you outline here. I just voted to reopen it.
As of today the stated reason for closing your post reads "This question does not appear to be about law", which is inaccurate. Your question clearly is about the interpretation of binding clauses upon which the parties purportedly agreed. This implies that your question pertains to contract law, as you correctly reflected by including the tag
The reason why I did not answer your post when I first read it is that I am not acquainted enough with the functionality of the [Amazon] service in order to infer the provider's intended scope of "non-transferable". For instance, allowing an account to have multiple credit cards with different holder names suggests that Amazon did not intend a stringent meaning of the term "non-transferable". Amazon could have implemented a simple validation so that all cards match one same name, and yet the company evidently declined to do so.
Had I known that others would rush to close your question, I would have answered it (as sketched in the preceding paragraph) notwithstanding my gaps regarding that aspect of Amazon accounts.