I
think Big John knew exactly what he meant.
He is more of an authority on guns/tactics/lethal force training than the 100s of "new-hires" or the hard-chargers who think teaching new students is easy.
Many high end/top level instructors do
not bad-mouth or rail against other tactics instructors as a matter of professional curtesy
but I'm sure they would not spend their $$$ on some classes. On the flip-side, many like Massad Ayoob take courses or advanced skill training then praise top notch schools & cadre.
I've been around firearms & formal classes since the 1990s. I've seen great gun trainers & programs. I've also seen range cadre or licensed instructors I wouldn't trust with a TV remote or a bag of marshmellows.