a Christmas Nazis will get offend with any business that even utters the word happy holidays.
Doing so will cause them to accuse you of being part of a conspiracy against their cultural/religious views. See The War on Christmas
During the Christmas Holiday Season other religions are supposed to take the back seat regardless of what the American people think.
In short these overly aggressive Religious nuts turn a Holiday that supposed to Unite people in Christian Fellowship into a Holiday that express hate toward those who practice their right to Religious Freedom. It's also a cash cow for the leaders of the Religious Right
Christmas Nazi + Conspiracy + Propaganda merchandice = Profit and discord.