According to Sky Sports News, Jonathan Barnett reacted after Bale was jeered by fans at the Santiago Bernabeu Stadium on Saturday, with Real losing 1-0 to Barcelona in El Clasico.
Bale was substituted shortly after the hour mark, leading to his agent's comments after a stinging reaction from the home crowd.
"This generation of Real fans will be talking about Gareth's goals for years to come. Frankly they should be ashamed of themselves. Gareth deserves the greatest of respect. The way the Real fans have treated Gareth is nothing short of a disgrace. In the six years he has been in Spain, he has won everything. He's one of the best players in the world. Those fans should be kissing his feet."
It has been a difficult period for Bale after winning his fourth UEFA Champions League with Real last term.
The Wales international has been dogged with injury, which has affected his potency and form in the Spanish capital.
Cristiano Ronaldo's exit last summer has aided Real's collapse in La Liga, with Barca sprinting 12 points ahead of their rivals in the Spanish title race.
Bale has been unable to inspire his team in the same manner as the Portuguese did before his sale to Juventus.
Barnett also criticised the Spanish press, adding their inaccurate portrayal of the forward has damaged the player's reputation, but noted Bale wishes to remain with his club (per Sky Sports News):
"Despite what the Spanish press are reporting, he's happy, he speaks reasonable Spanish and there is no problem between him and the rest of the Real players. The people writing these things know nothing about him. There has not been one single discussion about Gareth leaving Madrid. He isn't going anywhere this summer. Despite what's been reported, he's content, he wants to stay at Real and they want him."
The former Tottenham Hotspur winger has passed the century mark of goals scored since signing in 2013-14, but he has failed to hit 20 goals or more in any one campaign in La Liga.
This represents a failure, with Bale previously expected to fill Ronaldo's formidable scoring boots once his career with Madrid was over.
Europe could represent Real's salvation this term. The team have won the last three Champions League titles and are 2-1 up against Ajax ahead of their second-leg clash in the round of 16.
At 29, Bale has achieved everything he desired in Spain. A move to a major Premier League club could be appealing next summer if Real decide to bring in a fresh collection of superstars to the Bernabeu.