The Barca teen had gone into the El Clasico having declared Real Madrid "are always stealing", before also posting to social media a message to Los Merengues, insisting they do not worry him.
Yamal was targeted by Real players at the final whistle, with many - including captain Dani Carvajal - making 'talking' gestures with their hands.
At the final whistle, De Jong was asked about the end of match brawl: "I didn't see the situation. I didn't see it because I was on the pitch and I only saw a lot of players and the staff.
"When the final whistle blew, a lot of people headed towards Lamine. I think that's a bit of an exaggeration. Just ask them.
"Lamine didn't say they steal. He's in the Kings League, they create a favorable situation for him at the table, but Lamine didn't say it directly. It's a bit of an exaggeration."
On Carvajal's taunts aimed at Yamal, De Jong added: "You can also call him privately. If you're Lamine's teammate and you know him, you can call him instead of making gestures on the pitch."