It's not a question of "branding someone a traitor". There was an embargo against Serbia at the time, and the 1992 Fischer-Spassky chess match constituted a major commercial transaction (considering the press coverage and the $5 million prize money at stake). The State Department told Fischer about the consequences of playing the game well before it happened -- not only did he play the game anyway, he spat upon the letter from the State Department. IMHO he got pretty much what he deserved for that sort of behavior -- why not just play the match somewhere else, anyway?

Did anyone die when he spat on the letter? I don't care for his political views either. But I don't think anyone should be chased around the world like that because of the views they hold.

He wasn't chased around the world for spitting, or for the views he held -- he was accused of violating the trade embargo, which is a serious allegation.

I would have violated the trade embargo for prize money that big.