I've never heard anyone use "knighthood" to colloquially describe lesser Commonwealth honours. (Here in Australia, certainly, we've gone back and forth on whether we have knighthoods, and when the Abbott Government briefly reintroduced knighthoods a few years ago it was a huge deal - and very distinct from other grades of honours.)

The journalist is American, presumably, and the US doesn't have direct equivalents to the hierarchical orders that Commonwealth countries have, so maybe they just assume that knighthood means something much broader than it does.

The colloquial (blasé) term is 'gong'.

'Nobody' calls the non-knighthood honours (nor the order as a whole) 'knighthoods'.

The author made a few pretty sloppy mistakes, sadly.