I would agree with this statement. I think part of the reason is because even very minor differences in a coin can have very large impacts on value. Just look at the difference between a 63 and 64 graded coin - potentially a huge difference. From my experience, the foreign coin market isn't as hypersensitive to differences in grading, and doesn't place as much emphasis on imperfections. And you are correct that the TPGs are often more liberal. They grade based on general market acceptability. What you experience here on CoinTalk is an exaggerated microcosm. We'll point out every flaw, and because we are judging from pictures we'll even point out flaws that don't exist. I'd love it if every single coin in my collection were of the highest, most original, eye appealing quality - but in reality sometimes that's not possible. Yes it is. It's just considered market acceptable when done properly and not too much.
No it’s not. At best conservation but it’s not considered anything when you can’t even tell that it was done when done properly. Guessing that it was done because of color is just that a guess.