I don't get co-workers with BS nerd comments like that... I am guessing they take very little pride in what they do? When I am working on a car, it isn't my car, it is a customers car, and respecting that simple fact means a lot to me. My job is to make it better, not worse, and that means not dirtying it up.
I won't lie or bs, I am not a polish my tools kind of guy, but there is nothing nerdy about taking care of a several thousand dollar investment. If you want to wax your box, wax your box! Personally, I don't care if it looks new, I just want to make sure it is taken care of. So I clean it, along with my tools, with the goal of not rusting, and so forth. I haven't waxed my box, and likely never will, and I am sure I will have a "dull" paint job down the road, but for me that isn't why I clean it. I clean it so it lasts for $2000 worth of time.
Most of all, anyone willing to go off and call people names like that shouldn't even get a second of meaningful attention from you. Co-workers or not, they are not friends, and their opinion means very little considering you are doing the right thing.
Being moral and ethical isn't about popular opinion, it is about being truthfully correct in your actions. Taking care of large investments is a truthfully correct action. Even if the OP question is a bit "n00bish", I think we can all agree that there is nothing wrong with wanting to take care of your tools, box, and so forth.