Sometimes a point is well made even if I disagree with it, the conclusion in it or disagree with the path it suggests whilst agreeing with the objectives.

It's like how in Politics in better times (or less adversarial countries) one might respect a political oponent whilst disagreeing with them.

There's also a trait in some cultures were people tend to try and poke holes on other people's ideas and point out the bits they find incorrect, not because they're against it, in disagreement with it or to put down that other person, but to try and help improve that idea even further - in other words, genuine constructive criticism. A downvote isn't constructive, and sometimes people deserve an upvote for trying or for how far they got, even if the end result could be better.

When I agree with a comment, but the rebuttal is civil, well thought out, and reasonable, I’ll upvote both. I’m more likely to downvote attitudes I don’t like rather than statements.

Yes

Many discussion topics can be complex and are much more than one side or the other, so I've found doing this in the sense of replying that I agree on these parts, however...

"Why should I break my head about the outside world? Let the outside world break it's own head!"

"He's right. As the good book says, if you spit in the air, it lands in your face."

"Nonsense! You can't close your eyes to what's happening in the world."

"...He's right."

"He's right, and he's right, they can't both be right."

"You know, you are also right."

If it's a civil and interesting discussion, why not?

This is actually the way you are supposed to do it.

I do this

One can appreciate a strong argument, even if it goes against what they themselves believe.

Upvotes are supposed to represent that a comment added to the conversation in some way. Just because two individuals disagree doesn't mean that they didn't contribute.

For me:

Upvote = worth your time to read

Downvote = not worth your time

I almost never even downvote because it's an active choice to push down someone's opinion.

I upvote everyone I interact with ... positive, negative, agreeable, disagreeable, questionable, correct, incorrect, dumb, intelligent ... the only time I downvote is if someone is genuinely advocating violence or death or murder against anyone

Yes.