They are using lay terminology, but it doesn’t matter for regulatory affairs: authorization, approval, and clearance are legally distinct and companies are fined for using the wrong word.
Easy english could be a reasonable excuse if the precise terminology would be indecipherable to laypersons, but I don't see that here. "FDA grants emergency use authorization [...]" would give the exactly same diffuse "they allowed something on some level" information to people like me who are unaware of the specifics, but without ruining it for those in the know.