I don't see why people think its unethical to get LL if you are above average. Silly sure, thats a fine opinion, but to say its unethical just sounds like someone who's below average and can't do the surgery and is bitter that they can't even get to that persons starting height.
At the end of the day LL is just as ethical as getting braces, or any other cosmetic augmentation. You could also argue its the same as buying a fancy car or nice house. That raises your value and improves your quality of life, but is it unethical to do so just because you are wealthy and someone else isn't, and just further flaunts what you have and they don't? Of course its not unethical-everyone is constantly doing things to raise their value- get a better job, get whiter teeth, get into shape.
LL is a hard process, if someone is willing to raise the funds to do it, regardless of their starting height theres nothing wrong with doing so. Even if their parents pay for it, they are still sacrificing their time and dealing with plenty of pain. There was someone who finished lengthening as I got here who had been a bit taller than me pre lengthening, and did two operations to gain 1 3/4 inches TOTAL, blowing 200k or so in the process. Sure that came from his parents and could have gone towards something else to raise is value so to speak, but for being willing to brutalize his body twice and lengthen the tiny bit he did, perfectly accounting for his proportions, power to him.
Lastly, its pointless to argue the ethics since this is kind of something that will never come up since no one knows what LL is for the most part and no short guy will ever be getting laughed at by some tall guy and be shouting about how his height is an unnatural abomination since he got it at an average height.