The world record for bench press was 500lb in the 50`s and it took 15 years for someone to break this record and then in the late 60`s someone hit 615. Use your head , what do think happened in those 15 years? It jumped up 115 lb instantly as soon as the juice hit the scene, before the juice 500 was the absolute limit and only done by one man.
Try taking your own advice and use your head. Guys who were hitting 500 lbs were big, burly dudes, pushing 300 lbs. Now, we have guys who can do that naturally, that are in the low 200s (i.e. Chris Bell). A handful are under 200.
Drugs are hardly the lone or primary reason strength records have been equaled or exceeded by more people. One, there are more people involved in lifting than there were, back in the day.
Two, nutrition and training techniques have improved as well. In days of yore, only one guy could run a mile under 4 minutes. Now, plenty of people have done such. Does that mean they're all sticking syringes in their behinds? NOPE!!
So, your take that people barely over 200 can bench 500+ naturally but someone pushing three bills can't do the same with 600 makes no sense.
Back to Fletcher, he has done about as much as one could do, to make his point. Nearly all his lifts were in drug-tested federations, some of which test randomly (not just the day of the show or meet). And, he competes in arguably the strictest natural bodybuilding federation there is.
The law of averages would suggest that, were he cheating or doing half the mess you claim he is, he'd been caught by now or someone would have exposed him.
Having benched over 400 myself drug-free, while being nowhere near Fletcher's size, I hardly see such a feat (pushing 600+, without steroids) as unachievable.
If you want to believe that, such is your business.