Interesting thread if you're serious. Depends on the relationship you have with the guy. Did he rub in the Egg Bowl, even in a joking fashion? If so it's probably ok; you have a history of friendly rivalry or **** talking.
Otherwise you're the guy sitting next to him who was kind of an ******* for no reason. If he's your drinking buddy it's one thing (and some people are thin-skinned about stuff like this even then), but if it's the guy who signs your paychecks that's another. I'm not saying you have to kiss his ***, but ripping on him or the things he loves might not add much to the Christmas bonus. Conversely, he may not give a **** at all... but usually if that's the case frowning and stewing about it isn't the response.
I have a State fan in my family who loves to rub it in when State beats OM and I just choose not to talk sports with him, win or lose. I personally don't get a lot of joy out of rubbing it in when we win and I really don't like it when others rub it in when we lose. I totally get that other people aren't wired the same way I am, and this isn't an OM vs State thing. I'm a "friendly rivalry"/"good game" kind of guy, and I just don't hang out with **** talkers.