In the past, the claim was that pre-computer photographic compositing techniques were used to compose the Apollo photos from background and foreground elements. That's only if the claimant managed to think at all beyond the "looks wrong, therefore fake" position. If reasons are given, it's along the lines of a workflow that allowed for better compartmentalization, or an overall lower number of participants. They can argue, for example, that the landscape backgrounds came from unmanned landers, and that they could reuse the same backgrounds for a number of photos. And then other photographers could be employed to take photos of foreground elements in other surroundings, telling them it was for editorial purposes. And a few photo guys working in a secret darkroom cutting the photos together would involve fewer people that whole crews operating an all-up photo shoot.
But the problem is still that it's a stupid way to fake photos, if that was the intent. The key argument in all cases was that the fiducials were on the background plates to begin with, and therefore had to be worked around when adding foreground elements. If you want fiducials in the image, and you want the whole image to be consistent and coherent, you put the reseau plate in the final process camera and leave the fiducials out of everything else. It takes all of a few seconds to think of that. The problem remains only if the backgrounds were convenience resources, obtained from a source NASA didn't control. But there would have been countless other ways to get what they wanted, without the fiducials.
And of course the hoax claimants always cherry-pick the photos and leave out those that don't conform to their claims, such as those where the fiducial is only faded and not obliterated entirely, or where the fiducial is selectively absent only in the bright areas of some individual foreground element. I think the funniest counterexample is one where a fiducial overlays the U.S. flag, and the fiducials are missing over the white stripes but visible over the red ones. Did we really need to composite in only the white stripes?