I recently came across user Sola Gratia. "Sola Gratia" is a Christian concept. Their profile pic is a cross. Although this user's answers don't seem to include anything inherently Christian he doesn't usually quote Jewish sources other than the Tanakh. It doesn't sit right with me to have a user on a Jewish website with a profile pic depicting a cross. A cross is to me a symbol of Jewish persecution much like the swastika. What can we do about this? Should we do anything?
I asked a question about the broader case of usernames/avatars offensive to some (but not all) sites two years ago on Mother Meta. There doesn't seem to have been a strong consensus. Many said it should be handled on a case-by-case basis, which isn't really helpful to understand the "real" rules of adjudication.
The golden rule
In this case, let's consider the practical effect of censoring this user's name or avatar. If we establish precedent that explicitly Christian avatars or usernames are unacceptable here, we are potentially granting permission to other sites to censor Jewish profiles. I don't want to hear Buddhism.SE or Islam.SE claim, "Well, Mi Yodeya doesn't allow any non-Jewish religious avatars or usernames, so we will be censoring any users from there who show up here with avatars containing Torah scrolls, menorahs, or stars of David."
What about other faiths?
Do we object only to overtly Christian avatars/usernames or do we object to any religion other than Judaism in avatars and usernames? For example, would the user MuhammadIsProphet with a crescent moon avatar be acceptable? What about a user whose avatar is a Babylonian idol? What about a Ganesh avatar? Where do we stop?
We already have the tools to handle missionary posting
In justice systems generally, there is a principle of not expanding tools and actions to additional scenarios if there are existing actions and procedures to handle them. In other words, don't try to "creatively" charge a drunk driver with an industrial equipment safety charge if the standard charge of DUI is still available.
So, we do have an existing system for handling missionary preachers. Missionary content is off-topic at minimum and could potentially be seen as Rude (red-flaggable) content if egregious or repeated. We have automated question/answer bans as well as manual moderator-imposed suspensions for low-quality content and rude to others. Use these tools and let people have the avatars they want.
- If someone has a Christian avatar but is here to discuss Judaism in good faith, then there's no real problem except some mild discomfort which is part of living in this world.
- If someone has a Christian avatar and is here to preach for their faith, then warn and then ban them.