I once bought a pair of albino Pelvicachromis subocellatus. Since that fish is extremely rare in the hobby, I was surprised at an albino form being available. So I bred them to see, and got a lot of normally coloured fry, as well as albinos. As I suspected, they were Pelvicachromis pulcher, the common krib, and that's what I sold both the albinos and non albinos as.
I've bred a lot of fish, and have had a couple of albinos show up. I imagine large scale breeders like fish farms get them showing up often enough to work with them.
I used to get very upset at fancy forms and GMO fish in the hobby. Now, I just think your fish are boring if they're linebred, though I will politely call them "interesting". This will never be an ecologically responsible, oriented toward science and learning pastime. It's an ornamental fish trade, and only a small percentage of hobbyists care about wild form or not.
If you have a neon green angelfish, it's no worse than a pearlscale deformity, or a veilfin. Enjoy it. You can even try to sell it to me, and I promise I'll say it's interesting.