Maybe this is a Northeastern thing, but I have no idea why anyone would be bothered by someone interrupting a stupid person as he tells lie after lie. If I were in the same room as someone like Mike Pence, I'd talk over him too.
The problem is that Kaine wasn't just trying to talk over Pence when Pence supposedly lied, but in times when he should have just shut his mouth, like when Pence said he was in Washington during 9/11. I don't think anyone did a word cloud for the debate, but I wouldn't be surprised if the number one word associated with Kaine during the debate was "obnoxious". He interrupted far too much.