I'm not sure why so many are against insulating the pipes in a heated space. It can not hurt anything to do so. And if your RV has any air infiltration around those pipes on a below freezing windy night, that insulation will be the difference in having or not having frozen pipes.
I grew up in PA with a father that was a plumber. I've seen frozen pipes on many occasions. All it takes is a hairline crack in a block wall for the below freezing air to make a nearby pipe freeze solid.And this happens in heated sticks and bricks homes every winter.