In the United States, federal law prohibits professors from releasing any student's grades to any party other than the student and any party whom the student authorizes to receive the grades.
One of my professors appears to be violating this law by uploading each student's lab grades in one file, which is accessible to anyone who is enrolled in the class.
Here is my proposed plan of action:
Ask the professor - in private - to post the grades using the online management system the professor already uses for other things.
If the professor doesn't fix this privacy violation, inform the professor that the method by which he/she post grades is a violation of federal law.
As a last resort, contact the department dean.
Objetively, I think you should ask a lawyer just to be sure before taking it to the dean, since it's a federal law violation and acussing someone of that would make a huge deal. And you wouldn't want to make a fuss over something for being ill informed.
Personally, I think you shouldn't care whether your professor uploads your grades where somene else can see them or not (even if it's a crime or whatever, i wouldn't give a single care).
Good luck with whatever you decide to do.