Well, its certainly much easier to upvote than to write a comment - you don't have to actually justify your upvote nor will the words be scrutinized. If you feel happy with MSFT products, you can just upvote, but if you don't like them you can't just say "Well, I don't agree!".

And the lack of downvotes can be explained by another phenomenon - there is no incentive for some to downvote a comment like yours at this point, because nearly all replies are negative! If a comment thread surfaces some bad things about someone you don't like, and it becomes popular, you actually want it to become more popular isn't it?