It is part of a set of objects chosen in whole or in part by other players. e.g., “Each player kills a unit they control” does not target. Each player, including the one who played the spell, chooses a unit to kill as the spell or ability resolves.
§ 355.10.e Core Rules PDF (officieel)
§ 355 2. Make relevant choices.
§ 355.10 A game object, player, or zone mentioned in the text of a spell, activated ability, or triggered ability is a target UNLESS any of the following are true:
