Your points are well presented, and has its charms. However, even if you are 100% correct, your points still do not invalidate the viewpoints and sentiments of other residents.
1. The first question to ask here is;
am I invalidating the viewpoints and sentiments of offended residents? No, I fully recognize the aircraft noises and I even presented a few other residential areas, regardless of public or private, who are also suffering from aircraft noises. I believe that is your own interpretation of my words which seemed to be misplaced.
You fault buyers of HDB flats in Punggol, and subsequent complainants of aircraft noise with ignorance of airbase locations and flight paths, and insufficient due diligence; essentially caveat emptor or "buyers beware". However, HDB is selling (or leasing) a property; presumably fit for people to live in, to bring up children etc. The property needs to be fit for the purpose.
2. Here's an analogy. You visited a pasar malam and bought a China-made product, well aware that most China-made products are defective and of low quality. Do you still continue to buy it with the awareness and by means of your own free will, then complain about the company for producing defective products? What you brought up above still does not eradicate the fact that you have other available choices. Even if it means costing an extra few dollars for a more reliable product.
Regarding the "National Security" argument, I do not remember anyone arguing in this forum that it is invalid. However, let's not swing to the other extreme, and turn it into FUD (Fear, uncertainty and doubt), there are plenty of NSMen and their families in Punggol. We are all doing our part helping to defend the country. I am curious as to why you are dressing down residents who are simply making known their sentiments? The previous posts complaining about the noise are written in a manner that is cranky, yes, quite a number of them. malicious, no.
3. Please kindly highlight specific references that I am disregarding the contributions of NSmen living in Punggol. Seriously, I don't think you want to get this wrong with such an allegation on an open forum.
Regarding "How low is too low?", rules are set by people, people can and do make mistakes. If a resident think that a propeller plane may be flying too low, it is logical, and perhaps a duty to send feedback. If it is possible for the plane to fly higher, if it is safer, and if it is less noisy, the question why not fly higher needs to be asked of the correct people. If the time comes when a resident, and in particular, Singaporeans, cannot ask about the planes, cannot complain about the noise, I will then wonder if the country is worth defending.
4. As the SAF language goes, you think you think who confirm!?
(Another fact is, nobody bothers to confirm it.) However, if you are to step forth and say aircrafts are flying too low based merely on your visuals, I'm afraid you could be the one terribly wrong. Just like in a swimming pool (especially for parents who send their kids for swimming lessons), visuals can play tricks on your eyes too. Hence, you are right to say people can and do make mistakes.
EdLee, I read the thrust of your message as life is tough, suck it up.
You are free to read my message in any manner you deem fit. I can place a yellow lemon before you and you still insist it's a red apple, there's nothing I can do about it. But just to set the record straight, you are wrong.

There are always two sides to a coin. Now, are you open enough for the counter-arguments towards the complaints? Hopefully by then, you are ready to deliver some facts by the time we share some sentiments again. Cheers!
basilleaf: Well, my parents haven't had a day of peace for the past four years. Lift upgrading (2 years), new communal area construction (2 years) and now carpark works (so far 3 months). So I can fully understand what you're feeling.