Meaning that all the odds aligned in favor of him being a janitor and cleaning up. No, him getting the pentakill doesn't mean stomping. The probability of getting a pentakill is extremely low. The closest I've seen a pro coming into multiple pentakills in one game, would be TSM vs TL last year, when Wildturtle racked up a pentakill in a base defense, and followed that on the next base defense with a quadra. A pentakill doesn't guarantee you a win, as the Wildturtle penta/quadra chain was in a losing effort.
It doesn't matter on the champion used for the pentakill(one of the regions had a Teemo pentakill), as any champion can be used, if you're lucky enough and you build the champion right. Hell, I've gotten one with a full AP Sejuani before.
Pentakills don't mean that there's a stomp in the game, nor is it a disrespectful or embarrassing moment. What's disrespectful or embarrassing, is if a key player tilts on more then a few occasions, or he/she tilts because of something that's preventable. Huni's been known to do both.