So you know exactly what I'm talking about and just want to muddy the waters. Great! Fun!
I mean it's fun for extending internet arguments but not for helping anyone out here.
You got water in the pipes because you were using an industrial amount of air. Not an issue for drying out a revolver frame. Unless you've got a tiny tank, it's not even likely to kick on when drying off the parts. You're not gonna be spraying water out of the hose on a well maintained residential or shop size compressor. If you are, the tank needs to be drained, it was plumbed wrong, or you're dealing with a very tiny compressor.
You're also choosing to ignore that the water that gets trapped in the air tank, and even the water that could condense in the line, means that the air coming out of the end of the hose is quite a bit drier than the air you're standing around breathing.
Do I even need to get into the fact that a residential/shop size compressor is probably a piston design, and if it kicks on while you're blowing stuff off, it also starts spraying oil vapor on the gun?
It most certainly has a definite impact on the finish. Every spot of rust that shows up corrodes underneath the bluing next to it, and it'l just be worse the next it happens. Every time you have to scrub it off, you thin the bluing. And if you don't remove it all, and it just disappears because you used an oily rag to wipe it, it'l still be there under the oil continuing to corrode the finish.
I mean some people like the worn look, but pretending you can let bluing rust over and over without consequence is just silly.