I may be entirely wrong, but I was under the impression that this simply leverages amazon's affiliate program, in which amazon rewards 3rd parties for linking to them. That wouldn't be any sort of public relations play by Amazon, since the policy is transparent to the actual customers.

That doesn't address your point about the tradeoffs involved - if you object enough to Amazon's policies to forgo the benefits, that is entirely your prerogative. Just pointing out that this isn't a case of Amazon baiting people by appearing charitable - rather, some is providing a way to leverage Amazon's existing policies to have Amazon pay commissions on your sale for charity.