Hi Les,
I agree with you. It is not so much the content of the picture, nor how it was 'created', it the dishonesty of claiming it to be genuine. Genuine photographers were/ are only too keen to explain their techniques, be it darkroom or software related. Sometimes those 'modifications' took more skill than capturing the original images.
If the groups administrators are not prepared to listen to the truth, you are better off out of it.
Regarding copying in woodturing, I take it as a real compliment when I see any of my work 'copied' as it implies the turner was genuinely interested in what I had demonstrated. But the key difference is that turners can't 'cut and paste' from the original, they still have to be able to produce the work themselves. I suppose it would be like cutting four legs off a piece of Chippendale and fixing them to another chair, then trying to claim the new piece was a Chippendale.
Merry Xmas,