[scarmig]

You're conflating explanation with justification. Being a pissy asshole like described is explanable, but not justified: it betrays a deep lack of professionalism, and is a giant black mark on the interviewer.

Equivalent situation: If someone turns up 30 minutes late because they wanted to catch a couple extra zs, that's also understandable, but is just as unjustified and makes them just as much a jackass.

As professionals, we are called to treat everyone with dignity and respect, no matter what bug happened to crawl up our ass this morning.