Can I edit this answer to my own question to make it more polite? Around 50% of that answer criticizes my question. What is the SE policy to dealing with such answers? Should they be flagged (perhaps not this case, but in more extreme cases) or edited?
You're right, that was inappropriate - relatively mildly so, compared to some of what we get, but still inappropriate. I edited it to fix it. (The original is of course still visible as revision 1.)
In the future, you can edit it yourself, or you can flag it if you're not sure. Just keep in mind the cardinal rule of editing, that you should not change the essential meaning of the post.