I think the idea was since the guns would be available to multiple employees with various levels of gun proficiency, simple was better. Hard to screw up a point-and-shoot wheel gun.
You reckon the employees had no training with the Rossi's? And if they did, do you think it's difficult to learn the mechanics of a 1911 .45?
Learning to use a semi-auto isn't that complicated. It's not like trying to learn to speak Basque.
It's nice that the owner put all those guns there for the employees to use if they needed them. A lot of corporations that run convenience stores forbid the store employees from having guns to protect themselves. Of course, the lamestream media will never criticize those corporations. They'll be too busy whining about Halliburton.