First of all, it's not just that he selects what songs enter the voting. He manipulated results afterwards, with the stupid excuse of "just removing fraudulent votes"

As for "he was State Security informant" - that's really important factor to consider because it tells a lot about person's character. I mean what kind of scumbag would voluntarily provide information that might put people who did nothing wrong, other than oposing communist government, in jail, or worse yet, killed by "unknown perpetrators"? And for what - money, chance to advance his career? Once an asshole, always an asshole.