The reason she's pissed isn't because they think she's a secretary, it's because they apparently didn't consider it a possibility that she was anything else. The fact that she's a woman is likely the cause of that. I can't imagine that they considered that she might be the hiring manager or potential team member and then decided to go straight to asking them to do stuff instead of asking what their role is first. They also then go on to presume that she might not even be able to explain what the company does (which seems like it would be insulting to someone who is an actual receptionist).
I'm shocked people assume anyone's roles. It's not like it's uncommon to send down the hiring manager, first interviewer, potential teammate, etc to pick up interviewees.