If this is sarcasm I don't find it funny. If someone thought you were serious you could reinforce that view in them, and this is obviously not okay to not just do but for a photo for social media it's egregious. If you are being serious that feels like a bit of a "mask off" moment.
We have the freedom speech, but we don't put it above all the other basic rights and thus, it has well defined boundaries.
Edit: Also freedom of speech often seems to be interpreted as freedom from opposition. Yet, telling someone they are a scumbag because they are repeating nazi ideology ist totally in accordance with that.
Also for whatever reason people seem to think freedom of speech is also freedom from consequences. Her freedom of speech was not infringed, she simply got fired because she decided to do a stupid thing in public.