Honestly cannot blame them, all the fanboys that never had a interest in buying Xbox one are just bashing the system again and again. So when someone genuinely interested in checking out the new console reads the comment may get turned off because they are getting biased misinformed information that isn't even complete.
Take vgchartz for example. Every new Xbox One thread being made the same few people comment on it and bash it. Now when you take that to a much bigger scale and you can see why M$ disabled the comments cause its just giving misinformation that can potentially turn off interested consumers from the system.