I liked the poem though, as I think you identified, it is rather morose and bitter-sweet.

The video had me happy and interested for the first half... but when he said (paraphrasing) "There is No Excuse not to be happy" that upset me. He's literally saying if you're sad it's your fault -- It completely disregards the entire existence of depression, or even just sadness as part of the human condition -- and that in my opinion is not just an irresponsible assertion to make but a dangerous one.

Depression is truly a disease, like other which turn the body against itself, the mind is turned against itself. Fears that 'everything is your own fault', that you 'deserve what you get', and that 'nobody else is as stupid to feel like you do' plague the minds of depressed persons; the disease reinforces a negative feedback loop where it sucks your motivation, your capability to be happy and your desire to continue. For him to create a video titled "How to be happy" and then drop that bomb on his viewers is just... cruel.