People who are more likely to say that they agree with you or disagree with you are more likely to be people of little depth or substance. They won't have standards or perspective. They won't have a clue, usually. They're caught up in other things--going along, fake labels, political posturing, virtue signaling. They aren't invested in what is true. Truth will be lost on them. They want accordance, and often accordance at all cost. Not for the greater good--for their needs. They seek confirmation not of abilities that they have--mental abilities--but ones that they wish to have, need to think they have. They will call people friends who are not their friends, so that they can be seen citing those other people as friends. They won't listen. They won't learn. Life is not about these things for them.
The person who says, "I agree with you," or measures life in terms of agreement--and note how often they say some version of that phrase--is not someone invested in truth, and not that open to truth. Appearance, agenda, false virtue, and a validation that is not real validation is what they are about. They are credit whores, often. Not always, but typically. They are always insecure.
Further: be aware of how rare it is for something to both be true, and to be accepted. If you are saying things that are true, you will always have problems with this kind of person. Any relationship you might have in these situations, will be underwritten by how much you're able to tolerate. It won't be fellowship, and it won't be respect.
Note how rarely, for instance, I've ever said I agree or disagree with someone. The person who speaks this way is content with fool's gold in many aspects of life, and certainly the mental and intellectual aspects.
When you say "I agree" or "I disagree," it is almost always about you, and wanting to feel good enough, or self-congratulating yourself that you are. It's not about life, it's not about truth, it's not about reality, it's not about what is real. It's a way to claim levels on which one does not really belong--to make some leap as if to say, "See? I am a smart one, too."
And besides being so indicative of insecurity and narcissism, it's uninteresting. Is there a bigger prompter of the inward query of, "Who cares?" than someone saying they agree or disagree?