It's entirely unnecessary to make the problem (Santa hat) go away.
The complaining person is displaying abusive behavior and should be treated as such. Warn them. Then ban them if they persist. You stand up to bullies or you drown in them.
Mods can trivially and entirely disregard the non-problem (as it actually is). They're choosing not to and are making a community handling mistake in the process.
The only proper response is to ignore the complaint as not meaningful enough to warrant action. Otherwise you'll eventually have to remove every possible symbol. Somewhere, someone's mother was murdered by a cog and they feel very, very sensitive about the matter.
Abusive behavior in communities occurs at both extremes. You can be too sensitive in social situations in fact, to such a degree that you abuse other people with your need to control your environment specifically to your aggressively selfish satisfaction.