"hes not good at teaching"
Ahh, sod off with these excuses.
Zoro said a random word to a weakass kid and he became a chad shogun the same arc.
Rayleigh is dogshit at teaching anything as well. His methods are Garp tier. Abandoning a child on an island with dangerous animals. What a dumb piece of shit.
"Okay kid, I am done beating you with a bamboo rod. You live here on your own now. You may die or may not. idk, idc. I am off getting blasted again. See ya. Or not, lmao"
Its obviously not about the teaching in OP.
His crew is simple not meant to have it.