Can someone explain it to me?

It's Monday and I have a question that I must find the answer to: Why do stores such as Walgreen's and CVS put razor blades in locked display cases? I don't get this. I can buy condoms, personal lubricants, I can by all sorts of medications, I can purchase $30.00 exfoliating cream but I have to get an assistant (or "team member", that's a later