I have zero issue with him playing for Rangers. In the 00's that was the done thing if you were a standout in a team in the SPL outside they two, he just so happened to go to Rangers. It's not like he went to Hearts or anything in a sideways move.
I thought some of the abuse he got in his final stages of the last spell was quite poor, and I say that while personally thinking he played too prominent a role in our starting XI for what he could deliver consistently at that time. But he was a professional who gave everything to the club and deserved more respect than from the usual moaners who like to abuse players before supporting them.