No, DOCs and PDFs aren't necessarily software, they can contain software, just like a webpage. And just like a webpage, Stallman can choose to use FOSS to view those files, and that software can choose to not run any scripts in those files.
I'm sure he'd agree that people should also not include proprietary software in those files as well, but doing so is far less common than webpages, at least for stuff the average user is going to run into.
And how many people are actually programming in HTML/CSS vs JavaScript? A proof of concept is one thing, but most users won't run into it.