+1 for your point #4
doesn't meet the standard of "add[ing] new information" that you quoted from the FAQ. In other words, it doesn't convey anything particularly useful to the person reading your comment. It just adds noise. We can tell it was upvoted by the fact that the post's score incremented by 1.
I suppose the implicit assumption on the part of the reader is supposed to be "Oh, he didn't specifically give 'props' to points #1-3, so he must not like those." But it doesn't actually say that, and it certainly doesn't tell us why you disagree with those points.
However, compare your comment to something like:
I disagree with your points #1-3 because those are implementation-defined. If you're targeting an embedded system, you shouldn't do that. But point #4 is very good and bears more emphasis, so +1.
I wouldn't delete that comment, and I'd have to take issue with any moderator who did.
This time, I've managed to express my agreement with point #4, but more importantly, I've conveyed some additional useful information. I've explained specifically what I dislike about or disagree regarding points #1-3, but still conveyed that point #4 was so good that the post merited an upvote anyway.
Alternatively, you could explain why point #4 was so useful or expand more on how it might relate to the question at hand. I do that a lot, perhaps because I don't know enough about the rest of the topic domain to post a full answer, but I can convey something additional about one of the minor points.
So basically, there's a right way and a wrong way to do this. The standard is whether or not you convey any additional, useful information beyond the fact that you upvoted (or downvoted).