Another funny thing is that he doesn't seem to know what secular means.
A Christian can be as secular as a religious person. All secular means is that a society should be organised so that folks should be permitted freely to make their own religious choices, including whether they believe in any sort of God whatsoever.
That means, no majority can force an individual to inhabit a religious environment of which they don't approve. Another name for this is religious freedom. This is something which was a triumph of the west during the Enlightenment: it solved the issue of religious wars, which have been a problem everywhere in the world basically for all time beforehand.
Barr has a pre-Enlightenment belief system. He wants to elevate his beliefs above those who don't hold them. He wants to force conformity to uniformity, which is exactly what caused the problems in the first place. If any country knows this, America should. It's kinda embarrassing that the AG is this ignorant.