Pique, who said quitting would play into the hands of his detractors, was jeered in an open training session with Spain on Monday.
He had broken down in tears on Sunday following the violent incidents in his home region as police tried to prevent would-be voters from taking part in the banned referendum.
The defender, who voted on Sunday, suggested then that he would be open to walking away from international football if coach Julen Lopetegui or his team mates felt uncomfortable with his presence.
He said on Wednesday, however, that he was fully committed to the team.
"I considered it (quitting the Spain team) but in the end you have to evaluate every option and after thinking about it for a long time that I decided not to as leaving now would be letting the people who insult me win," Pique told a news conference.
"I believe the people who boo me are a minority and I don't want to give them the luxury of quitting. I have every confidence that there are many people, including in this group, who want me to stay and help the team win matches."
Lopetegui said now was the time for the team to focus on Friday's World Cup qualifier with Albania, where Spain could seal their place in next year's tournament in Russia.
He called on the fans to back Pique.
"We have to move on now with Pique and now is the time to concentrate on the game," the coach told Radio Marca.
"To play well we'll need the support of the fans. I want to talk about football, the team needs to talk about football."
Pique, 30, has played 91 games for Spain and won the 2010 World Cup and 2012 European Championships with his country.
He announced last year his intention to retire from international football after the World Cup, due to a combination of repeated criticism from the media and supporters, and to give other players an opportunity.
"It's impossible to doubt my commitment to the national team, I've been coming here since I was 15, I consider this to be my family. I'm proud to play for Spain and it hurts me that people doubt that," he said.
Pique also reiterated that he has never spoken out in favour of Catalan independence, and simply supports the right of his home region to decide on its own future.
"Speaking about politics is troublesome, but we are people before footballers. Everyone can have an opinion, so why can't footballers," he added.
"I'm not an activist. People have advised me not to talk about politics but I never put myself on one side or the other, all I said was that we should vote."
(Reporting by Richard Martin; Editing by Christian Radnedge and Toby Davis)
