I usually respond to different comments from different people by using a separate post, since that is common sense.
So why does this rule exist ?
What would the forum look like if all sig spammers made multiple replies like you ?
What does your common sense think about that ?
I think he doesn't understand importance of rules and that's why saying such things. If multiple consecutive posts aren't allowed then there's of course a reason for that and some people really don't understand such things. Multiple replies don't make sense when one could easily quote multiple user's comments within a single post. I guess he should rethink and take his words back.