Actually this is what you called spamming. It's really understandable why they give you a warning
I'm sorry, I don't understand what you mean. I've never gotten a warning.
Also I thought spamming is for really annoying, off-topic randomness. I'm just saying there's nothing wrong with acknowledging something someone else said. That's just polite conversation to me. Or if all you can say is "I agree," then at least you've shown one more person agrees with what ever the other person said for example...there's value in that, because it's information. Information = post quality to me.