Guarin was caught in possession for the equaliser, then the Nerazzurri had to fight back from 2-1 down to earn a point.
"We started out well and didn't allow Torino to control the game, then we made a big collective error," said Stramaccioni.
"In a tough game like this at San Siro, you can't just throw away a lead. I don't intend to blame an individual, as it was an issue for the whole team and we were caught unprepared.
"In order to try to win the game, we left spaces for Torino and they could've punished us further. At the end of the day I think the draw was the right result.
"Guarin? He made a mistake, but these things can happen to everyone, including me. It was a bad mistake, but we can't blame anyone individually."