scooby's not at fault for giving input on how he thinks they should be done.
There is nothing wrong with isolation.
You do not need to be at some arbitrary strength level to toss in some curls and pushdowns at the end of a workout.
The "no iso" line is just typical guru BS strung about to be the scapegoat for the bigger problem internet writers can't address because people won't keep coming back.
It isn't the curls fault no one makes progress. It isn't even the routine.
It is the complete and total lack of:
3) personal accountability
5) even half ass quality eating habits.
90% of beginners meet all 5 if not most of the above. Out of the 100% that will start lifting this year, 90% won't be by the same time next year, and 99% will have quit by the time NOOB gains come to a grinding halt and you need to fight, scratch and bust your ass for every minor gain.
"Isolation" exercises get villainized because weak souled people that are there to go through the motions are doing them, constantly, because they are easy, and god forbid they break a sweat.
It's the trainee's fault, not the lift, not the program... But you can't say that, because you don't make any money off the 1%.
That being said, Scooby is a doofus who's back doesn't match his chest, and I highly doubt, considering his age, is a lifetime natty... Not that I judge them, but it's dishonest to sell that body (front at least) to newbs on a 50 year old man, when he is deffo on TRT or was on something in teh past.