Says who?
As far as I'm concerned, its a team and no one is above doing ANY part of the job. That means that progress notes are most definitely not just for interns.

at whatever senior resident pulled that one on you.
Truthfully, there are some places and teams which are more hierarchical and it will vary from program to program, and rotation to rotation.
We had a PGY-3 who tried that "its intern work" thing and got a talking to from the PD about how we worked as a team and to stop trying to act like a PGY-3 was above doing certain chores. That's how my program rolled.