As popular as Bullfighting is in Spain, I wouldn't bet on any ban happening anytime soon. And I hardly think some protest by activists will cause a ban anytime soon. It's just too popular by the voting majority... and the voting majority is who decides election outcomes.
Ok, 250,000 signatures huh? Of course, those signatures were from all over the place, not just Barcelona. I have to ask, why would ANY city, or government official heading into an election, give a rat's ass what some activist in another city or country thinks? Unless the candidate's position on this topic harms their chances of getting elected or harms revenues, I would think they really won't care about some petition from those not in a position to elect them to office. Would you? I certainly wouldn't. I would focus on what the VOTERS want.