It seemed a bit discourteous of the crowd.

The native born Canadian made no big thing of his native nation's flag being absent, and instead spoke. Meanwhile, as best as I could make it out over the noise, the boorish crowd more than once shouted in unison, "In your rump, in your rump."

I believe that was what they shouted. YouTube it yourself, see what they say.

Reader help on that detail via a comment would be appreciated.

_____________UPDATE_____________
I watched it again. All he seemed to be saying was honor the Constitution, and vote your conscience. Perhaps the suggestion of having a conscience, collectively or individually, got them riled up.