The StackExchange network works best for getting answers to (very) specific questions. This means that each question should include the goal of the question and the intended audience. Your original question contained neither, and was thus not well received.
I think the comments largely stemmed from the lack of this crucial context. Someone even took the effort of looking into your profile, to see if your background could help in identifying what exactly you wanted to know. Instead, they found that you have an engineering background, so one might ask, how can you not know basic pressure vessel formulas? Why would you directly relate the thickness of the exterior of a vehicle to the safety of the associated mode of transportation? To an engineer, that is almost akin to asking "Why are airplanes so safe, even though they have so many wheels?".
The comments, collectively speaking, tried to identify where your reasoning was so apparently misguided that you would ask this particular question, perhaps somewhat incredulous that an aerospace engineer would ask such a thing. Only then, it was discovered that the actual question read "How can I explain to the member of the general public that 1-2mm makes for safe air travel", so only then it became clear what the goal of the question was (how can I explain it to someone else), and what the intended audience was (someone who knows how to do engineering, but does not know how to explain this to laymen).
So, in conclusion, your original question did not reflect what you actually wanted to ask. As a result, the comment section contains some misunderstandings, which on the Internet are easily mistaken for "pooh-pooing" and "wisecracking" - perhaps due to cultural differences (being a Dutchman, I know many people would find my feedback rude, while I feel that gift-wrapping critique benefits no-one) or just due to the brevity and permanency of comments. My advice would be to assume good faith, and see all comments as people taking their time to help you answer your question. Only when you find people are insulting you personally or completely off-topic, you should flag comments; furthermore, once the comments have helped you rephrase your question, you may flag these comments as obsolete and forget they ever happened.
On a side note, this meta question title reads "What is the intended public for Aviation.SE", while the body asks about the content of comments. In response to the question title, I might add that you should ask questions that you want to have answered, not that you think others might want to know. From Help: Don't Ask: You should only ask practical, answerable questions based on actual problems that you face. So while the intended target of Aviation.SE includes the general public, you yourself are an expert, and do not need to ask all the questions the general public might ask.