"Exfiltration of confidential business-sensitive documents" could be nefariously downloading proprietary research for personal gain... or innocently downloading a Slides presentation to your personal phone as a PDF in preparation for a client meeting in case it's impossible to connect to their Wi-Fi. Or saving e-mail communications with your manager in case you need them for personal legal defense purposes.
Companies can be amazing at twisting innocent actions into horrible-sounding policy violations when they want.
I'm not saying this is the case, I'm just saying we don't have enough information to jump to a conclusion.