3 players?. your either blind or something he has 1-2 pages of players sold or bought.
Please read the entire quote: there are exactly three players that he sold for a decent profit within a month of purchasing them.
If you want to see an example of abusive sellers, I can point you to someone. But this guy? Nah, he mostly seems to be training some guys, making some purchases, and for the most part keeps them for a significant period (and when he does sell again quickly, it's not a significant markup).
Of course, all that information is freely available to you as well. If you think he's flipping players to the point of having such a dramatic advantage, list five guys that you feel meet that category. Or don't, because you can't, and just keep finding someone or something else to point the finger at.