Nobody is offended. It's just football fans looking for reasons to make fun of a team they don't like. It's only Nazi like because it's red and black which is associated with the flag of Nazi Germany and uses an art style very vaguely reminiscent of Nazi symbolism. But football fans are going to look for any excuse to make fun of teams they don't support.
Plus, the article makes it out like it's a bigger deal than it is. It's just a few joke mems posted in response to the Falcons social media posts. Nothing more.