Wait. People are disgusted about the job of a corrections officer?! That's a thing? I didn't know that was a thing.
If people are making a face at you (and they haven't said anything), you may just be able to get away with a genuine smile and, "I'm pretty excited about it. Bean dip?"
If they do say something, then I'd suggest the same smile plus saying with pride, "It's not a job for everyone, but it is a job for me. Bean dip?"
I used to handle those looks like this. It is what I always considered good etiquette: the other person flubbed up and was a bit rude, I'll smooth it over so no one is uncomfortable.
I've learned not to be so quick to do that. If the person seems to catch themselves, maybe an oops look on their face or something, then I'll smooth it over. Otherwise, I cool off the interaction a bit and don't try to hide the fact that I'm offended. IME, the people that do things like this are repeat offenders.
I'm not rude or mean about it. I just pull back a notch: my smile and tone becomes just a bit cooler, I pause briefly before responding, etc. I'm still polite about it, but I no longer respond with "niceness" if that makes sense. I get far more respect.