This is a terrible straw man.

Firstly I have raised two bugs against LibreOffice in the last decade where it can't open files it created and can't print a spreadsheet.

Secondly the specifications for proprietary software are not necessarily closed: https://learn.microsoft.com/en-us/openspecs/office_file_form...

The only thing here is that crap software is crap software. And Word is crap software.