Earlier quoted context omitted.
The recruiters do that because lots of HR departments are explicit: docx or deleted. Once you get through the screen, you can show them your fancy resume, but at that point, no one cares about your resume -- you already caught their attention and it is interview / references time.
Haha. If a company doesn't want to hire me because my resume is not in .docx format, I probably don't want to be working there anyway!
But companies also have a zillion "well if they don't want to work with me I don't want them working here" rules.
Listen, sometimes in the real world you have to do something a little unpleasant every now and then. Candidates should bend a little to employers, and employers should bend a little for candidates.