The player who changes teams can become a villain without changing how they play.

A player who moves clubs can be recast as a traitor without altering a single thing about how they play. The change is entirely in the allegiance of the person judging, and yet it produces genuine hostility. Loyalty here is a property assigned by others rather than a quality of the person.

The same happens to anyone who leaves a workplace, a group, or a community. Expect that the reaction may have little to do with your conduct. And if you are on the other side of it, watching someone go, it is worth separating what you feel about their leaving from any conclusion about who they turned out to be.