Xavi has criticised Real Madrid for failing to give departing captain Iker Casillas the send-off he deserved before his switch to Porto.
Casillas appeared alone at a farewell press conference on Sunday and struggled to hold back the tears as he said his goodbye to the club he joined as nine-year-old.
A wave of criticism followed, with Casillas's parents claiming in a newspaper interview their son had been forced out of the club by president Florentino Perez.
Real responded by organising an official presentation with Perez and Casillas at the Bernabeu on Monday, when hundreds of fans who turned up in sweltering heat chanted for the president to quit and gave Casillas a rousing ovation.
The contrast between Sunday's surreal appearance and the send-off Barca gave his close friend and former Spain team-mate was telling.
A product of Barca's academy, Xavi, 35, joined Qatari side Al Sadd at the end of last season, and fans, officials and team mates paid homage to him at a packed Nou Camp stadium where the midfielder was surrounded by family and friends.
"That's why it leaves a bad taste what is happening with him now," Xavi wrote in Spanish daily La Vanguardia on Tuesday.
"In recent years, I have seen that he is not enjoying himself like before.
"He even seems bitter and I think everyone in this country (Spain) should think about this.
"It cannot be that maturing Spanish athletes are not shown sufficient respect, that people neglect to value everything they have done for their sport and instead focus on their defects, sometimes with malicious intent."
Real Madrid organizeed a proper send-off for Iker Casillas on Monday.
Xavi drew a comparison with Juventus and Italy keeper Gianluigi Buffon, who he said still appeared to be enjoying himself in goal at the age of 37.
"I look at Iker and I have the feeling that lately he is playing under pressure, as if he has to prove what a great keeper he is in every match, without the joy he always had.
"Now he is going to Porto and I am sure he will be welcomed as a hero. Away from here they will appreciate him more."
