I've been in hiring discussions where word doc is looked down on since the candidate is not thinking about how to protect their data from manipulation.
This ladies take is dumb as hell, or as others have mentioned because her company changes applicants information.
Then stop using automated software that excludes candidates if the entirety of the job description isn't embedded in the resume. You're not special. You're just another job. And 90%+ of companies use dumb filtering so people have to adapt or get used to 2k+ applications per interview.
I think they meant that the document can look significantly different based on the software reading it? Whereas a published PDF is going to look basically the same (embedded fonts, etc)