Look, I'll be blunt here because I don't want to keep feeding this conversation:
The only reason why you're so fixated on swordsmanship and bamboo is because you don't know better, because you're too ignorant on this issue to know beyond and therefore believe this staple of cutting bamboo is more important than it actually is. Oda doesn't give a shit, Oda didn't see "a swordsman cutting bamboo" as something so relevant that he must put it in his work because he's Japanese, because he has it normalized, because he knows more than you do. Oda went for the tiger overcoming the obstacle in the form of Torao beating the Demon Bamboo from his past who seemed like an unbeatable wall because of his armament haki. The tiger achieved it and slashed the obstacle, whether it was through sheer swordsmanship or not is pointless; that's the symbolism, period.
You are obsessed with swordsmanship cutting through bamboo? That's your problem, not Oda's. I don't know, just learn more about Japan so a sword cutting bamboo doesn't sound so fundamental and transcendent to you. Because it's not.