Indeed the first link says in part:
>"I think it's ok to use the up and down arrows to express agreement."
Which reads to me as having an implicit "also to express agreement" especially in the context of the thread. The thread consensus appears to favour not downvoting for mere disagreement (but I would say that !).
In the past when we had votes visible we'd have been able to tell better the general consensus from that information.
So, I upvoted you for making your point well; presumably you downvoted me as you disagreed.