Student or Learner
Usually, one legalizes an activity, so I'm wondering whether one can also legalize statutes or rules, i.e., make them lawful. What do you think?
I wouldn't say "legalize a statute or a rule", as statutes and rules would typically direct what is legal and what is not legal, or what is okay to do and not okay to do.
You could take a look at "statute" here. Corpus of Contemporary American English (COCA)
And here: British National Corpus (BYU-BNC)