What Arch is saying is that people pretended to not have read the manga when they have, then made fake predictions based on actual knowledge of what will transpire.

If this was made into a single cour show, it would have sucked so badly that manga fans would condemn the show. Right now, it is doing quite well. The limiter release was hinted at in a previous episode where it was mentioned that Murmur was constricted by such a handicap made by Deus.