It's a really good point about Apple willfully using an Experian service as part of this strategy. As to defamation, I don't think that's clear. Apple is intentionally using the term to be as legally vague as possible about how it externally reports its past connection to its ex-payees. This is mostly liability management, essentially saying less that can't be called false, instead of the defamatory tactic of saying more that is not true.

  as·so·ci·ate (n)
  1. a partner or colleague in business or at work.
  2. a person with limited or subordinate membership of an organization.
  3. joined or connected with an organization or business.
                 - Source: Google search results fed by Oxford Languages

This kind of vague hedging in communication for legal purposes is pretty longterm characteristic of the organization. It's the "say absolutely nothing after termination that can be dissected in court later" school. The school has adherents all over the place.