What I wonder, why would someone go out of their way and trying to discredit Grusch because he had PTS? Is that all part of the game to make his testimony seem

What I wonder, why would someone go out of their way and trying to discredit Grusch because he had PTS? Is that all part of the game to make his testimony seem more plausible? Or just a bad attempt at smearing his reputation? Idk.