Actually, it can.
The idle power with screen on on an efficient Haswell system is about 3-4W. The rest of the system is not inactive on HD playback, so they'll consume power on top of that. Even the SSD/HDD will be using power. Intel improved a lot with Haswell but don't expect others to be zero.
It shows right there on the review you linked how much power the SoC is consuming, which is 6W, which is at max.
No, I am not excusing for the Core M, which is a poor excuse for a product paraded as next "Conroe". But you should do more research as well.
Regarding Carrizo, I do expect nice surprises from the product, and probably get the closest to Intel products in years. Their 15W product I am expecting 2.4 points in Cinebench R11.5, which makes it competitive with Broadwell 15W. Their graphics will be quite fantastic for the price, on the 35W part pratically bringing Iris Pro 6200 performance without the price(and without the eDRAM which tells how horrible Intel GPU architecture is).