I downvoted all three.

In the first case, my downvote had nothing to do with whether you'd read the entire article or not. It had to do with your apparent lack of understanding of the purpose of the site. You came very close to suggesting that rationality and irrationality are subjective, and essentially indicated that you think rationality shouldn't be valued as highly as is the norm here. The comments about other posters' rationality seemed inappropriate, too: We're here to learn to be more rational, and all of us have areas of irrationality to work on.

The downvote in the second case was based primarily on tone: Morendil offered what appears to me to be a suggestion on how to avoid being downvoted in the future (I'll grant that it's not the best advice that could have been given, but it seems to me to have been given in good faith if nothing else), and you responded in a way that looks both defensive and status-oriented to me, without actually adding any useful information. Such reactions are rarely useful, especially here. If you'd stated your disagreement in a way that opened the issue up for discussion, rather than apparently trying to end the conversation by asserting dominance, I wouldn't've downvoted you. In fact, I may even have upvoted in that case; I like to see good discussions of our group norms - at least, the norms that don't define the group.