Someone still bitter about losing to an injured Murray at IW in 07 I see
Andy very rarely calls the trainer, so that's actually a load of crap.
Does he spend a lot of time on court clutching at something, pulling faces, or touching his knee, his back, whatever? Yes he does. Is he injured or faking it? Nobody can know except him and what you choose to believe probably depends on whether you like him or not in the first place. If you like him you give him the benefit of the doubt. If you don't you probably cry "gamesmanship".
Either way, it doesn't really matter - the opponent has to get past these things and play the ball, not the guy or his on-court antics, tough as that may be. If you ask Murray I'm sure he'd say Haas is entitled to his opinion but that Haas is wrong. I'm sure Murray doesn't give a fiddler's toss what Haas or anyone else thinks about this.
If you define gamesmanship as "disrupting the natural flow of the match to try to gain advantage" then there are many, many players out there with many different tricks that are gamesmanship, most of which are not actually breaking any rules, so you have to deal with them and not hide behind this as an excuse when you then lose to them.