You're not your organization's meeting monitor. The only times you should address this issue are when it's your direct report who's being rude, or when a peer's rudeness at a meeting has an impact on your work. Be direct and explain why the behavior hurt you. Your peer will respond with an excuse for their behavior, truthful or not. Always act as if the excuse is true and remark that it was out of character, whether it was or wasn't. Provide them with a solution for future meetings and hint that the behavior was so egregious that it couldn't help but be noticed by others.
This script can be modified to: