Cherry picking is easy. Fighting guys who are past prime, no where near the threat they were 5 or more years ago is easy. Or fighting guys that went life and death with Berto is easy. Anything is easy when you choose the easiest path of resistance.
He means , All work is easy when you pick guys at the right time.
"All work is easy work".
Just look at his resume and when he fought guys like Cotto/Mosley/Pacquiao.
All work is easy work
That all "work" he chooses has been made easy beforehand by cherrypicking the opponent whether due to quality or because they are past their prime. Therefore, when it's work time, it should be "easy".