system
A chat on subreddit /r/NoStupidQuestions
human
Aside from the moral implications the reason is cost. Sure the company doesn't take the biggest hit but someone is paying for it and that someone is everyone that is a consumer at said store. Insurance costs to cover theft, loss prevention teams, camera systems all cost money. They will recoup their money one way or another and it will be the consumer who pays.
gpt
People make it seem like it's one guy stealing one thing from a big corporation which is no big deal. That one theft might not matter but if it's happening a few times a day at each location that stuff adds up even with tax right off. They aren't just going to lose money, they will increase prices to make up for it. 

Also who are you actually stealing from? The big corporation or the franchise owner? I worked at a convenience store. The profits were shared between the corporation and the owners of that particular franchise. The losses were 100% on the franchise owner who couldn't just increase prices to make up for it.