Actually he doesn't at all say a film HAS to be escapism, just that this film doesn't offer it, it doesn't say films that don't offer it are bad, just that this certainly isn't escapism, its a hell on earth story thats as gritty and real as possible. In that he's right.
As for the review he has a point, normally these types of films are made because they are horrible situation turned good, or a tale of learning and growth, or planet being threatened with destruction but they win in the end.
He has a point, its just a gritty story about a horrible existance, nothing more or less, its not uplifting, theres no happy ending. Its just watching the painful existance of someone and thats it, there really is no real reason for seeing it and that was his point, which, is pretty fair and accurate.
Imagine Forrest GUmp without all the happy bits and without him being happy at the end, it would just be a story about a sad disabled kid, who didn't do anything and we just get to see him being abused.