Not for the first time this campaign, the Madrid boss has been forced to leap to the defence of the French striker due to his underwhelming form.
Benzema has struck just four goals all season in La Liga from 21 appearances, and his ratio in the Champions League is not much better - two in five, firing his latest blank against Paris Saint-Germain in midweek.
Taking into account the 30-year-old's return of 126 goals in 265 league outings across his near-decade at the Bernabeu, though, Zidane does not believe that he has to justify his decision to select the Frenchman.
"I don't have to say if [criticism of Benzema] is unfair or not," he told reporters at Friday's press conference. "I'm interested in the work he does; I would have liked him to score [against PSG] because he had chances, but what he did, he did well for the team.
"I don't have to convince anyone. There are people who know football and they know that Karim is very good. There are always players that people like or don't like. There are people who like Isco and people who don't, that's going to affect you and not me.
"Karim has been here for nine years and I don't have to defend him, he is very good, I like him a lot. His record speaks for itself. He is the No. 9 of Real Madrid and we only focus on him more because he hasn't scored much lately. What they are criticising is that he hasn't scored but he has done other things for the team and that goal is going to come."
PSG are one of four French clubs reportedly weighing up a summer move for Benzema.