Unfortunately, this is an issue, we have been told repetedly (believe me, this annoys a lot of people around here, has for a long time), that cannot be addressed because some individuals might edit their posts to hide potential inflamatory comments they make on the boards before the demis can catch them if a complain is lodged against said individuals (if they delete their posts, the demis can still see them, whereas whatever's edited out is lost). I think that's the gist of it but if I got it wrong, I let the demis post a more exact explanation

To be honest though, I completely agree with you. It's not just annoying because of the typos, but also because, when you write an academic post, it is very likely that you'll wish to come back to it at some point. Or if it's an RP post, you may have a new idea for a storyline you'd want to incorporate and you can't afford to delete your post because other posts follow building on yours

If my explanation as to why we face this 3-minutes limitation is indeed correct and thorough (i.e. it's the only reason why we are depraved of the right to edit our own posts), then I dare say this reason is unsatisfactory: for one, the chances that someone edits their post in order to hide a breach of the CoC are very, very small (I mean by that that it would be a very rare occurence), especially when compared to the fact that this limitation annoys people on a daily basis on this site. Moreover, why not suggest that people who feel there's a violation of the CoC and who fear the person might want to "hide" it (possible in particular in case of inflamatory remark) to take a print screen: it's an easy enough procedure....