I've been noticing lately (specifically on bigger deals), people responding to the first commenters post for the pure fact they want to push their agenda.
Would it be fair to report their comment as off topic if it has absolutely nothing to do with the person they responded to? Here's an example.
It's annoying, but it happens on nearly all internet forums with higher post counts.
Now I just wait until someone replies to my top level comment with an out of context joke…