Guardiola was charged by the Football Association (FA) for wearing the ribbon after Jordi Sanchez and Jordi Cuixart were placed in custody as part of the crackdown that followed last October's referendum on Catalan independence – a poll the national government in Madrid deemed to be illegal.
The FA deemed it a political message but former Barcelona boss Guardiola was in a defiant mood after City's 3-0 victory over Arsenal – his first piece of silverware since moving to England.
"I accept if I broke the rules. I accept the fine," Guardiola said. "I am a human being and there are four guys in prison plus another guy who is outside Catalonia - if he comes back, he will go to jail.
"They're being accused of rebelling - to be that you have to have weapons and they don't have weapons, they have just the votes in the ballots.
"That's why I said he's always with me until the last.
"It's not about politicians, it's about democracy. Before I'm a manager I'm a human being.
"I think England knows very well what it means. You did Brexit, you let the people have an opinion.
"You allowed Scotland to have a referendum if they're going to stay or not and after the people vote - that's what they're asking [in Catalonia] and they are in jail right now."