Hamilton announced on Friday that he would switch to Mercedes for 2013, ending a relationship with McLaren that began when the team spotted his potential in karting in his teens.
Although McLaren's recent form has been consistently stronger than Mercedes can boast, it is understood that other issues were brewing between Hamilton and his team - and Hill believes these tensions were insurmountable.
"Lewis has been like a caged bird at McLaren," Hill told the Daily Mail. "He'd been managed to within an inch of his life. I can't blame him for looking to move elsewhere.
"Lewis needed to leave McLaren to stretch his wings."
Hamilton said during the summer that McLaren's policy of keeping its drivers' race win trophies was a key factor in talks. Hill said he understood Hamilton's stance.
"I could never get my head around the logic that the team takes the driver's trophy," he said.
"It's the principle, not the trophy, that is at stake.
"After you have won a championship, and jumped through a lot of hoops, there is a point when you think: 'This is my life'. You can have a bellyful of becoming a performing seal. You don't want to be on probation for your whole career.
"Of course, you still have to fight inside the car; but there is a time when, surely, you have proved you can motivate yourself. These are things Lewis has tried to balance."