You might find it helpful to consult the site documentation (see the "Need Help??" link at the top of each page) which notes that a single downvote on a node likely has at least as much to do with the person casting the vote as with the node voted upon.

At the time you wrote this reply, you only had a single down-vote on the prior node. Escalating a single downvote into a yet another discussion about voting reasons often changes the types of votes you get, so the single down-vote might be the only one actually due to (one person's reaction to) just the prior node.

If you are really curious about why someone might downvote, besides the site documentation, you can read through many, many previous discussions on voting. It sounds like you, like most, don't downvote w/o a fairly serious reason. But that is just how most monks vote, not all of them. Some down-vote all of the time and almost never up-vote, so, obviously, they down-vote for less than serious reasons (or else they think the site is chock full of serious problems, I guess). Some monks have pet peaves. And, of course, everybody can have a bad day and take it out on somebody else.

Are you really so conceited that you can't even imagine some reason why someone might dislike your prior node? :)

Finally, some advise: Meta-discussion points such as your "link between the threads" are usually better received if they are accompanied by some non-meta-discussion points. That is, try to contribute to the main topic of the thread if you want to make some point about the discussion itself (not the topic of the discussion).