Thankfully, most modern Christians in the western world are good people.
They have a personal faith, built upon an ancient religion that relies on ancient scrolls.
Whether or not I agree with them is immaterial. Christians who act "christlike" are generally pleasant people to be around.
Again, I think any kind of worldview can get "mental" depending on the relative mental stability of the person engaged in it. Anyone think G Gordon Liddy is a great example of a Republican? Or Rush Limbaugh? Me neither. I don't think most Republicans are like that, even if the leaders of their political party spout off nonsense.
In the case of most nominal Christians, I don't take the rhetoric of their nuttiest leaders as speaking for them. Unless they personally choose to identify themselves with the fringe, at which point, the gloves come off.
Christianity is not a mental disorder. But there are Christians who are mental.