In the carry/issue states (states where they actually issue CCW permits, or states like Arizona where you have full freedom to carry without a permit), the etiquette and law of *where* to carry is still evolving.
In shady neighborhoods, of any kind, you definitely should. For a trip to a gas station, driving to work (and leaving your gun in the car), getting groceries, those are all trips where it makes sense to go armed, if the neighborhood is shady.
Of course there is a whole group of extremists who are advancing the extreme notion that one should always carry.
It is like in the adventure sports industry, where extremists evolve with their own extremist views as well. Skydiving, mountain climbing, scuba cave diving, these sports are fraught with danger and hence extremists evolve all over the place.
I would never bring a weapon into church, unless church was in a shady neighborhood.
I would never bring a weapon into work, unless the owners permit it, and it is a shady workplace, with no security.
I would never bring a weapon into a restaurant or bar or fitness facility, unless again that too was in a shady neighborhood.
Obviously I am not an extremist.
California is a may issue / but does not issue state. That means you just should not go into shady neighborhoods no matter why.
If this place is shady, and they won't let you carry, then don't go there.
If not, you don't need to carry.