Your example is a bad one in regards to users, be it devs or otherwise, but is a good example of how half-backed software is then given as example. In your case

Your example is a bad one in regards to users, be it devs or otherwise, but is a good example of how half-backed software is then given as example. In your case, if the goal was to only get values from dropdown, then make those cells behave properly. Constraints are easy to implement to allow only get values from dropdown and no typing allowed. So I'd blame the original developer of said Excel form instead of its dev users.