When I first saw a few genuine non-comics people occasionally use this term, it did not bother me. But it's on so many listings now, from long-time dealers and collectors ... c'mon, you sure as heck thought you could grade when you bought the damn thing, so offer your grade opinion when you sell! Who the heck thinks it's a guarantee and does not look at the pix and description??? Pictures, words, why you think it is in the grade range you think it is, disclosure of defects....these are the reasons I pull the trigger!
"Professional grader" implies there's a governing body providing licensure upon passage of a test. I'm not aware of the governing body that administers the CPG (certified professional grader) exam. Yes I realize they probably mean third-party grading when they say this, but it is not the same thing...one exists, one does not.