Gerard Pique went down under the challenge of Diego Llorente in the penalty area in the closing stages but his claims for a spot-kick were ignored and the incident wasn't looked at by VAR.
Earlier in the game, Busquets gave away a penalty for tugging on Diego Llorente's shirt at a corner.
"Controversy is always going to be there," Busquets said about VAR.
"There was wrestling for [Real Sociedad's] penalty. I can grab him, but if you set the bar there, it's going to be difficult.
"And the Pique one is proof because it was clearer than mine.
"The referee had to look at it, but there's not much you can do.
"I don't know why VAR didn't review it. VAR has to intervene in moments like this.
"But you can't keep going on about it, even though it's a moment that could've decided the game.
"There are combative moments, but penalties are clear...
"If difficult to know why they behave like this, because they don't make assessments or clarify it."