First of all I never said they couldn't sting- but you do have to go out of your way to be stung. How did you manage to get stung ? I have stood in the middle of their holes drinking a coffee and watched them fly and land on me and a neighbor and rest a minute before flying off. Solitary bees are not inclined to sting, being the queen if they get into a beef and lose there is no next generation. Now honeybees will sting to defend the colony and that is to their advantage.