Oh, ok, I'll bite.
First, a couple things....
First, any light contributes to light pollution, it doesn't have to shine upward to pollute. Think of it as noise. There's loud and blaring noise, and there's soft low volume noise. All break the stillness of the night. It's all a matter of degree. Bright white awning lights, flood lights, etc are like the sub-woofer thumpin' car, or guy with his windows down and stereo blasting at stoplight, or someone with big speakers blasting country western at the backyard BBQ. A dim light pointed at the ground still adds light to the darkness. It may not travel far, but the more people who use them, the more it adds up. It's like the cricket in the bush. One isn't loud, but add a bunch together....
The obvious: Which kind of light is better? Well, for specific tasks, a lot of light is very helpful. I doubt you'd find your heart surgeon using a soft underglow light in the operating room. I look at light as a tool, use it when needed, and put it away when not. Also, like noise, I do keep my neighbors in mind. They may have curtains, but I still think it's rude of me to leave a bright light on all night long that lights up their RV or campsite. Again, I think of light like noise. I may like sleeping with a radio on, but would never keep it up loud all night and expect my neighbor to wear earplugs because my noise is THEIR problem - so deal with it.
I will say, as a guy who's traveling with telescopes and likes to stargaze, I'll take indirect soft, low lumen lighting over bright glaring lights I can see a 1000 feet away. To those who say they turn out their lights at a certain time or prefer soft lighting over bright - thank you. I've been in too many campgrounds that resemble the neighborhood I left behind. Good lighting puts light only where needed, and only at the level required by the task.
Rodent fact: Yes, many rodents are nocturnal, but it's also a fact that they adapt to their environment, and rather quickly too. They are not static in their behavior. Thinking that they are is a very common mistake. Rodents invade, nest, and do damage in all kinds of brightly lit and noisy places. Industrial sites have rodent problems too. Also, remember that while a campground is a transient place for you, it isn't for the resident rodent. They live there full time so you showing up with your lights is nothing new. It's just another opportunity for survival. Once they determine there's no new danger, it's business as usual for foraging and nest building. That's why light, smells and noises aren't an effective deterrent. It doesn't take long before those irritants fade into the background. Where they might have some effect, is with low populations and areas where there's a lot of alternative places to forage and hide. Even still rodents will explore, and if your RV is easy to get into, presents excellent shelter, food and or/water. It's a score. I've told the story before if sitting in a char in my campsite, and watching the chipmunks case the "neighborhood." They'd go from site to site, stopping at all the usual entry point - power cords, sewer hoses, moving along under the RV stopping to look up for a place to enter. And those truck and RVs parked with their hoods up because that deters them from hiding under the hood? I could see dark outlines of chipmunks darting around the engine compartments or sitting on the air cleaner contently hanging out. Wild creatures perfectly adapted to their unnatural environment.
One thing people do all the time is connect two dots what may not be related. Correlation does not equal causation. Rver A may say they've done X and never had a rodent problem, and by doing so connects X with a particular outcome. It could be their particular RV was properly sealed at the factory, or the area has low pest pressure, and X had nothing to do with the lack of problems.
I've actually seen some good info in this thread. I will contradict one comment and that's about using bait. Yes, it does attract, because it is designed to, but yes, it is used to lower local populations. That's why bait is SOP in pest control for rodents, although not as a stand alone treatment. Because it attracts, it's best used outside. Feed them before they enter. It's also why stickyboards are preferred over baited traps for interior monitoring.
Back to underlights. Ive considered them too. Just can't convince myself I need them. Despite being the guy who wants to stargaze in total darkness (save my trusty dim red light for reading charts) I DO like cool lights. I upgraded my old single porchlight to a 12' LED strip light - one that is dimmable and can be set to various colors, including red for preserving night vision as I set-up my equipment. Same with my step lights. They either glow blue, or for stargazing nights, red. All go off when the need is done. If I need to go outside for any reason later, that's what the switch is for. On for the task, and back off when the task is done.
Wow, this was almost the perfect thread for a retired pest control guy who is also an amateur astronomer and full time RVer. Sometimes all the cosmic tumblers line up for a jackpot.