‘use strict’; is not there. It should work. FCC has it added in global space unknown to user. One the most important lessons you can learn is understanding what you call bad code. People usually get hired to fix legacy code. If a user was faced with a global variable situation where they did not have the luxury to modify it without redoing the entire script, they need to know how it works. And when the environment doesn’t inform us that there is ‘use strict’ is being used (which should be shown at top of function) it’s misleading. The code example I wrote is to demonstrate the flaw & not my own practices.
The use of ‘use strict’ is discussed in the curriculum. The reasons for it being a requirement in the FCC environment are discussed in the link I provided. If you strongly believe that making this a default that students cannot bypass is an error, you can log an issue on the FCC GitHub repo.