This is hardly a big issue is it Kellais? I do not even bother reading negative reviews of his books. I know before I read it that I will disagree. Because I love them. Simple as that.
I guess it depends on if you think reviews are important? If not, then it is not a big deal (but why then would you feel the need to downvote one?!)
If, like me, you think reviewers do an important job for us readers, i do think it is an issue (not a big issue if you compare to poverty and world hunger etc. sure, but i guess we can agree that we know that we are talking "in perspective"

). The up- and downvote button has a reason for being there and this is not to downvote reviews where you do not like the overall star result. It is for telling other readers which reviews are helpful as in "you can take something with you from reading it". So it is to downvote one-liner reviews like "This books stinks" or "Wow, best book ever!!!". It is decidedly NOT meant to be an instrument for fan-wars! And if you downvote a review just because you do not like the quality assignment the reviewer made (because you think Bakker should get a better one), then yes, this is not what it is intended for. Especially (but not exclusively) if you have not read the review at all.
Just imagine what you would think if, let us say, Terry Goodkind Fans would start to downvote all positive Bakker reviews on the grounds of "Just because Bakker sucks".
And just to be clear - i know that, most probably, lots of people use those buttons for exactly that. I just think this use of it is dishonest and manipulative. This is why those things are useless on amazon. Which is a shame. Because the idea is a sound one.
It's just that i kind of have higher expectations of the people on this forum.
Is that wrong of me?!

I agree this is democracy in action...but it should be democracy in action on grounds of "is this a good REVIEW" not "Is this a review i think i can agree with in its overall sentiment in respect to my favourite author"!
As to the fb comment...i agree there should be a dislike button. On the other hand, if you disagree with something, you can always make a comment to that effect. But yeah, even if i am on fb, i am not a big fan of it. I just use it to stay in touch with my friends that do not live close anymore. Everything else is of no use to me.