I always root for former Rams. Bettis, Dickerson, Everett, Gurley, Warner, hell, i even rooted for Bruce on the Niners. Not for them to win but for him to play well. Lots of former Rams either left on bad terms or rubbed the fans wrong. Who cares. They were Rams that contributed to Rams wins for years. Goff is just another in the list, but he lead us to the Superbowl (1 of 3 QB's to do that in over 70 years) and led the highest scoring, exciting to watch offenses we had in 2 decades. That is a ton of terrible Sundays of losing. Tons of 7-9 and 4-12 pathetic teams. Did it with a hurt Gurley and a season ending injury to Kupp around mid season.
I find it bizarre when fans say "he's dead to me" the minute he walks out the door. That's some next level lack of appreciation I don't get.
But to each their own. People see things different and have different perspectives as fans. So to each their own.