I wonder if Bieber's agent figures that the TWELVE YEAR-OLDS are the only ones still interested in him, so if they wanna keep the money rolling in, they'd be wise to do their best in appealing to that particular audience! Case in point: the video you mentioned.
Another possibility is that Justin himself suggested making a "happy feel-good" video that he can watch from time to time because of the bout with depression he's been dealing with as of late. Both he and his ex Selena Gomez have told the public about it
