This is really interesting. Fasting and shaving hair is something that Christian monks do. None of those images even come across to me as someone that would be druids or gothi. These are not believable depictions at all. Druids are known for wearing white robes and they even failed at that.
I don't know enough about Greeks but I recall them being depicted in artwork as having hair. Greek gods sometimes shown with long hair.
You're right about them projecting a lot, projecting themselves even. Christians attack pagans over things that they themselves do but worse. Then Jews love to throw project everyone else as incest and/or gay, and they even derive from the Hittites, their fictional foe a.k.a. themselves.
But it could also just be the producers not knowing shit about history. There are plenty of ancient and medieval movies with really poor depictions. Like that movie with Goldberg as her suit of armor is welded around her body. Movie and show producers often pull shit out of their ass it seems.