Here's why:
* He's not a true heir: Scar is Simba's uncle, but he's not in line for the throne. He's an outsider to the line of succession, leading to his bitterness and resentment.
* He's physically different: Scar's physical appearance with his darker fur and scarred face marks him as different from the other lions. This could be interpreted as a sign of his inner darkness and his alienation from the rest of the pride.
* He's manipulative and cunning: Scar's plotting and scheming to take over the Pride Lands set him apart from the other lions who prioritize the good of the pride.
* He's rejected by the pride: The other lions, especially Mufasa and Simba, reject Scar's ambition and his attempt to usurp the throne. This further reinforces his status as an outsider.
While Simba also experiences a period of isolation and alienation after his father's death, he ultimately returns to his rightful place as king. Scar, however, never fully belongs, and his outsider status leads to his downfall.