In any hobby, profession, religion, whatever, there will be people who only know one way of doing things and because it works, they assume it is the only way that works. Hobby stores have very high failure rates for exactly that reason. The owner KNOWS what works and will not tolerate other manufacturers, suppliers, methods or opinions.
The SLHBS I go to only has one big beef: using the main mill for specialty grains. Absolutely VERBOTEN. A real pain some times, but they want to keep it pure for the pilsners.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk