It seems a post gets about 10 minutes during which edits can be made. Perhaps an alternative to prohibiting edits after 10 minutes would be to make it so that edits are noted in the original text so that people can see what edits were made.

I don't know all the reasons for the limited edit window, but I imagine they are reasonable. One I can think of is the problem Facebook originally had with edits. One could make a highly offensive comment response, wait the people to pile on with angry messages, then delete the comment. Then it looks like everyone is piling on against the original post.

However, if it can be seen what the history of edits are, then you can't really deceive people with the edits. I would like to be able to edit spelling and grammar mistakes that I notice after the 10 minute window, or add additional points somehow when the commenters point out issues.