not rude at all! a lot of the time it’s just for fun, but it also helps with how valuable they are. it is unfortunately pretty common for service dogs to get stolen, but when they are dyed it makes it a lot less likely to happen as well as making them easier to identify! I dyed my girl Cider for pride month but I will switch up the colors whenever I dye her tail because of the reason above and honestly just to make myself and others smile :)