I'm a fan of Robert E Green's writing. That said, I don't know that I've noticed the floor standing "dip" phenomenon he mentions, at least insofar as being more common than among monitor speakers (i.e. I hear dips and colorations in both types of speakers).
I know that Mr. Green has long extolled the truthfulness of Harbeth speakers. I briefly owned the very well regarded Harbeth Super HL5plus speakers, on approved-height stands, in an acoustically excellent room.
They were really wonderful in some ways (vocals!) but I found my Thiel 3.7s beat them handily in just about every area I could think of, even in terms of the Thiels midrange sounding more substantial and believable.
So at least in my case, anecdotally, the BBC type monitor did not display the purported superiority over a larger floor stander.