I was pretty disappointed in reading those comments, but I'm also hopeful they're isolated incidents from people who, for whatever reason, might just be having a bad day.
People who are successful -- the real experts -- don't need to belittle others in order to feel better about themselves, and I'm hoping that new users who visit our site understand that when people boast about how great they are, it's because there's an area in their own lives that's really lacking and that this is just someone trying to make up for their own insecurities in some other area of their lives.
The really truly successful people, those who are truly happy with how their lives and careers have turned out, don't need to respond with such hostility, just because someone else may not physically be able to handle the same amount of stress that they did.
The bottom line is that we're trying to build a resource of knowledge to help people become more successful in the workplace. Rudeness, belittling comments, and participating only with the goal of making others feel bad is contrary to that goal and has no place here.
We all have our strengths and our weaknesses, even hardened military veterans who worked 50 hours a week and dug holes and cleaned rifles while studying for exams are weak at something. We all also have good days and bad days and are humans who make mistakes, but what we can do is this:
If you're having a bad day, before you post a comment, read it a couple times and put yourself in the shoes of the other person. Try to look at the world through their eyes. Think about something that you're not good at and imagine what it might feel like if someone better than you at that thing treated you the way you're about to treat this other person. None of us are good at everything, and if someone were to take a good long hard look, they can find our faults too.
Let's remember that the sole reason this site exists is to help the people coming from search engines who have real, actual problems. Without them, we don't have a site.
As for what to do when you see something like this happening, here's what you can do: When in doubt, flagging is usually the best option. You can flag a comment, or if the entire conversation has degraded you can also flag the post and use the Other (needs ♦ moderator attention) option. Our goal is to simply diffuse the situation and create a great site for asking and answering workplace questions.