I don’t think you got the central point. Protestants exist to protest Catholicism. A Protestant that recognises catholics as Christian’s wouldn’t be a Protestant.
Different sects of Protestantism are able to recognise other sects as Christian’s because a central tentant of Protestant practice is the personal relationship with God. So different sects of Protestants find that easier to accept. Where as Catholics practice a relationship with God that is tied to the organisation and the Pope.
Mormons are arguably a different religion altogether. Similar to how Jewish/Christian/Islam all share similar but different religious texts making them all different religions.
The intended outcome is othering.
You misunderstand reasonable. It does not mean good, more the natural conclusion given the context.
It would be hard to get a direct substitute that would work the same way when 3d printed. Even very small layer lines would interfere with the flow of the ink. For this type of application injection moulding is far superior.
Fluid dynamics is difficult, but someone may be able to design a pen that relies on the layer lines. But it won’t be easy.