Think they are confusing our agreed (loosely) stance, that 'units' aren't the way in modern CM...
For me, heavier muscular types, like that AC Milan player, Kessie, are not ideal in high intensity.
Muscle takes more oxygen to carry, simple biochemistry stuff, so high movement is often hampered, lactic builds quicker, etc.
However, if your training and conditioning teams are extremely savvy to this then it can work well in other positions (CB, ST, AM), but FB and CM not for me...
Less profound reservations now Poch and his ways are no longer here, mind you...