Posted By:
davidcycleI would say judging the grade of a card falls linguistically closer to a movie review that an expression that a company committed fraud by definition of such and such law. Graders themselves say grading isn't an exact science, so who would they be to say someone can't assign a different grade. Even when "I think" is omitted, saying "This card is overgraded" is understood to be one's personal take. Of course, just as a movie reviewer can use dubious logic and quote incorrect history, so can one's opinion on grade by based on dubious criteria. Presumably, fellow collectors are going to want your justification for your opinion, and will form their opinions if your justifications are valid. If your justification is that the image is faded, they might see that. If your justification is "Because I hate anything in a PSA holder," they likely will dismiss your grading opinions now and in the future.
If you can offer up reasonable (even if not universally agreed upon) basis for saying "That card is overgraded," I don't see any legal problem. There was a fair basis behind your opinion. If PSA, for example, doesn't weight strongly a card's image contrast, that doesn't mean you can't use it as a basis.