I lived north of the KC NP for many years (Wishon Res), encountered many bears and never a problem. Back packed, hunted, fished most of the trails. Oh sure they get into the trash cans and need to be chased off. The same idiots that feed the bears are the ones that use the bear spray indiscriminately. I don't know if it's banned in all NPs but I believe I was told it was in Yosemite.
If you think you need 'bear spray', carry it for piece of mine but it's not needed. Notice one responder mentioned carrying a side arm ……. asking for big trouble. It's illegal and must be declared when entering the park (must be in a locked/sealed container), Federal Law not California.
Look at it this way, you are the visitor, the bear is the resident and he has the Right Of Way ……. give it to him.