Huh. That's actually not a terrible idea.
I wouldn't automate moderation attached to that (yet), but to give people a tool to gauge if a responder is just disagreeing or is a frequent troll? Yeah, that could work. Better than having to dig through the literary works of some rando stuck in an argument with you when deciding whether to block or report them.
Worst case the summary isn't particularly accurate, but for the reasons you'd be digging through someone's post backlog that's not that big of a deal anyway.