From what I understand it has like an hour and a half of cutscenes. That's just about a full-length movie there. Also, it's not just the cutscenes that matter, but does the game try to come off like a movie? Lots of dialogue, heavy on the storyline, etc?
Also, there's nothing WRONG with that. It shouldn't be considered an insult to give something a slang term if it reflects what the creators were going for in the first place. For example, Mario's a "collect-a-thon", but I happen to love collect-a-thon games so my ears perk up when people use that term. If I enjoyed interactive movie games then people calling TLOU that name would be an indicator that maybe I should pick it up. Ain't nothing wrong with that!