I would guess that they, as everyone else, have worked with MS Office all their lives and can do whatever they need without thinking much in there. But libreoffice has some small differences that will break their workflow and will spend time learning how to workaround those instead of doing what they need. For example, my grip is that in MS I can redo the last operation with ctrl+y, where in libre it's ctrl+shift+y. They could very likely allow the former to behave like the latter when redo buffet is empty, but they don't.
I would guess that they, as everyone else, have worked with MS Office all their lives and can do whatever they need without thinking much in there. But libreoffice has some small differences that will break their workflow and will spend time learning how to workaround those instead of doing what they need. For example, my grip is that in MS I can redo the last operation with ctrl+y, where in libre it's ctrl+shift+y. They could very likely allow the former to behave like the latter when redo buffet is empty, but they don't.