I think that is the down side of critical thinking. You wont accept an idea unless you consider it your own. This is true for myself as well. Most of the times when "I agree!", I do so because I already had similar thoughts on my own.
If I get presented with a completely new idea or an idea that does not fit into my narrative, I think the best you could get out of me would be "interesting, I will look more into it"

I don't do this because I think it is a great way to debate, it is not. I am just trying to observe my own tendencies so I am aware of them.