That's such a mischaracterisation, I don't even know where to start. That Quay-guy obviously searched for "furin" on pubmed, found some papers (that don't even say that - and most definitely not for any coronaviruses) and thought it fit his thesis. If only viruses and infections were that simple!
> “At least 11 gain-of-function experiments, adding a furin site to make a virus more infective, are published in the open literature, including [by] Dr. Zhengli Shi, head of coronavirus research at the Wuhan Institute of Virology.”