you know what i mean.
anyway, being a fan undermines the ref's credibility. look at that lazio game, he made some controversial decisions despite var evidence. people can make mistakes, but in case he did those as a roma fan, then boom, it's technically a fixed game. let me ref any inda game and i promise you they're losing it.
even during calciopoli, there was no evidence for a single match that had his result influenced, so it's a serious thing. i don't know if there's any code of conduct for the refs (i guess there's must be one), but if there's any, i'm pretty sure it's not allowed for any ref to publicly cheer for a club until they are retired.
btw i'm not sure about these allegations. giacomelli had already officiated 5 matches for lazio as either a ref or a 4th official, and lazio always had a positive result (like winning at juve stadium):
https://us.soccerway.com/referees/piero-giacomelli/95387/matches/
immobile's red card was straight forward, the penalty not given to lazio was dubious even after seeing the replays. still, if he's proven to be a roma fan, he should be fired from the ref squad.