You are correct. But picture the author at work. Righteous indignation off the charts. Blood pressure up. Steam coming out of the ears. Beating the hell out of the keyboard. What’s grammar when you’re on the front lines of the war for social justice? Grammar is from the world of dead white men.
You’ve got a point there. The author was probably so angry she peed her pants.
Lots of Wellesley students got the vapors, and ended up mishearing what was being shouted, causing the celebrants about six weeks limbo-hell, until things were sorted out.