Van Persie struck in the fourth minute of added time to deny the Premier League leaders all three points at Old Trafford this evening.
However, the Dutchman was booked for removing his shirt in a passionate celebration afterwards, an incident which Van Gaal claimed was "not so smart".
"He did a stupid reaction after the goal," he told The Mirror. "You can be excited, but you don't have to pull your shirt off, because then you have a yellow card. It's not so smart."
The Red Devils face local rivals Manchester City at the Etihad Stadium on Sunday.