He was born and raised in Colorado (I sat near him the first day; we talked about it). Let me also clarify that I do not think he was rude to us but to the instructor to presume to tell him what he might or might not explain. Now, this is just a personal opinion, but I think the reason the instructor didn't miss a beat is because he is a Corrections Officer and is used to dealing with all sorts of people; I have nothing to substantiate that, but that's what I think. Bernie tone and facial expression were not of curiosity, I can tell you that much despite maybe not being able to directly explain it. It wasn't so much sarcasm or snarky as it was "na-na-na-boo-boo, I already know, but just in case all you rookies don't..." without being overtly so.
He might also be trying to prove to everyone that he is above a introductory level course--that he already knows this stuff and is therefore "better" than everyone else in the class.
Where I work, we have frequent projects that necessitate hiring large numbers of temporary workers. The nature of the projects requires that the temps have college degrees. There are large numbers of retired teachers who are our "regulars." The work is related to their profession and the majority of them are wonderful.
But these days, we get a lot of laid-off teachers, as well. Some of them have a need to show that they know more about what's going on that the full-time employees of the company. They will argue about minute points, quote research and hold up entire groups of people demanding to know why they have to do something a certain way, when their way is clearly better.
Part of me feels sorry for them, because it is a blow to your self-esteem to be laid-off or fired. I can see that they are trying to show that they are not redundant, not stupid, not worthless.
But the other part of me wants to stand up and yell at them, "Look, you are working on the last two weeks of a project that has been in the making for two years. I am at least as credentialed as you, and my other team members are probably more credentialed than you are. We are not going to change something because you think there's a better way. Your 'better way' was tested and rejected a year and a half ago. Just shut up and let us get on with the work. I have a deadline to meet here!"
I content myself with indicating that the worst offenders not be hired back. Which is a shame, because there's not a lot of work available here right now, and we are the highest paying temp employer around. But we can't risk breaking the deadline of a contract because someone needs to boost their self-esteem.