Luffy catching the harpoon and throwing it back at Nelson is symbolic of the revolutionary act of turning the weapons of one’s oppressors back against them. This is not dissimilar to guerilla warfare in which we particularly utilize the advantages offered to us by our smaller stature when compared to the larger force. Having quick reactions to ongoing shifts on the battleground creates a tangible benefit, but a larger force typically reacts slower with sluggish movement. Between Luffy & Nelson, Luffy is a smaller, agile, target, making him more difficult to hit at range, while Nelson is not only larger, but requires the coordination of a dozen people to carefully move his throne around, leaving him vulnerable to the reaction attack.
When Sanji says, “take out the leader and the troops all run for cover,” it comes across as a direct insult against the Marines, but this sentiment is equally true of most groupings. Leadership is a rare & valuable skill, requiring not only skill & know-how, but the time to carry out the task, as well. In many settings, when the leadership fails to deliver, for one reason or another, the entire project can easily fall apart entirely. While most things worth doing require the cooperation of many people working together, they also need a unified & harmonious direction that is both firm in goal and flexible in method. The Marines may retreat upon the defeat of their commodore, but that is not a particularly shocking response from anyone.
Last note, the millennial dragons appearing once every 1000 years feels like a reference to the turn of the millennium in the year 2000. This episode aired in late February of 2001, but Apis & Grandpa Rio were introduced in the first few episodes of January, and, contrary to popular belief, the 3rd Millenium A.D. started in 2001, not the year 2000. This added context adds a sweeping feel of connection to the setting, even more emphasized when I noticed the baby dragon hatchling strongly resembled my own 9-month-old daughter. Earlier today, my wife & I were discussing Feng Shui, and I mentioned how when I was traveling in China, a child once informed me that Feng Shui is meant to make your home comfortable for a visiting dragon. She appreciated how I had rearranged the living room furniture, and I told her I just did what made me feel comfortable, so I guess that makes me the millennial dragon.