How is reading a post saying "I don't care about this" any different than reading 15 saying "me too" and adding noting more to a conversation? I'm afraid you are just going to have to read it and get over it.
There is actually a significant difference between saying "I agree" (without commentary) and "I disagree" (without commentary). And why I know of football board that has a button for "+1" but requires an actual post to disagree.
If you agree, you need not explain what part you agree with or why, saying I agree with the entire prior post can be for the exact same reason as the OP.
OTOH, if you disagree. Is it with everything said, or just some? And what is your disagreement with, the data?, the conclustion?, the relevence?