Nope mostly credit Getty and AP

Yes, "credits" indeed. To agencies or to the photographer personally changes nothing. One of the photographers to whom I talked was requesting credits be given to the client for whom he'd made the image.
How many counter examples do I have to provide

You don't. Your claim that the practice is not standard is effectively disproved by exhibiting examples of major sites doing it. Your providing instances of sites which do not changes nothing.
> We don't *have* to do anything.

You start offering caption guarantees and we will

I have absolutely not suggested giving any sort of guarantee whatsoever, which would obviously be both stupid and infeasible. I have suggested making our users aware of the fact that giving credits in this way can in some cases be a constructive behaviour.
I think that we see, too often, people removing credits on principle, which discourages valuable contributors and serves no purpose. I believe that people should be educated in considering whether this is necessary or benefitial. That is all.
>And how would that be a problem ?

Generally it is not considered a good idea to advertise porn sites in
your image captions. "Prussian Blue courtesy of  all Jews should hang
inc" isn't even going to be legal in quite a number of countries.

Your first example (wetriffs) would not be a problem, in my opinion.
For your second example, we'd just refuse to run the credits. Once again, I never suggested that we guarantee credits, nor that giving credits should be systematic.
Incidentally, congratulations on your Godwin point.

-- Rama