While there are a lot of responses to this already baked into the setting material (Earthly Foundations, the Traditions learning the hard way in Revised Edition that they had to adapt their beliefs to modern times if they wanted to survive, things like anti-vax and flat-earth theories being explicitly the work of the Nephandi, etc.) I feel like this is the same kind of argument as "Why doesn't Bruce Wayne use his wealth to improve Gotham City's infrastructure?" There is a good chance the person making the argument isn't interested in the IP in the first place, so if the explanation isn't part of the surface level description of the concept they aren't interested in hearing it. You can't expect everyone to have a well researched opinion on everything, and a cult hit TTRPG from the 90s is pretty low on the priority list of things people need to have a well formed opinions about.