It always seems to happen during the worthwhile presentation:  the ongoing “side-bar conversation” that is loud enough to be heard in the street-bar on a Friday night.
There are 3 possible messages these people are sending with their rudeness:
- “I am a higher level employee than the person presenting, and I wish to make it abundantly clear that I don’t have to respect them.”
- “I am an equal level employee, but I know them, don’t respect them, and should be a higher level than them.”
- “I am a lower level employee, and a moron.”
In any case, you are being a disrespectful jerk. Do the rest of us a favor and stop it.