"What I want is for Sneijder to be fit and regain his form again. That must be his primary goal", said Van Gaal, who has left Sneijder out of squad for next week's friendly against Portugal.
"But at the moment, I have the impression that he doesn't understand.
"He spoke to reporters last week, indicating that he was disappointed that I did not tell him myself that he lost his place in the squad. But of all of the players, I talked to him the most and he should not have done that.
"I'm now forced to respond to his words, which is something I don't like to do."
Van Gaal said he had not ruled out recalling Sneijder for next year's World Cup, assuming the Dutch qualify.
"Of course I will keep following him," he said. "But the first thing I need him to do is to regain his form. If he succeeds in this, I will select him again.
"His qualities are undeniable, but his first serious game of the season is only after the upcoming Portugal match. The same goes for player like (midfielder) Nigel de Jong and (goalkeeper)Maarten Stekelenburg."