why there is no editing?

You CAN (and should) edit your post before you post it. There is a 'Preview' button next to the 'Post' button for this very purpose. You CANNOT edit your post after it has been posted because allowing people to do this could materially change the wording of a discussion or a response and any responses or comments could therefore lose their validity and may even make them nonsense or irrelevant. This was a conscious decision by the designers of MyLot and it will not be changed or modified. It is a "feature" of the site, not a "bug" or a shortcoming. Those who find it inconvenient to be unable to modify/edit posts after they have been posted are generally those who have not yet adapted to the way that MyLot works. Spellchecking is now available in nearly all browsers. If you do not see any red squiggly underlines when you are composing your post, you should explore the settings of your browser to see whether you need to install Dictionary add-ons or plugins for it. There may even be 'grammar checking' plugins available, though, to be honest, these can be more of a hindrance than a help. By using the 'Preview' button, you can see your discussion, response or comment exactly as it will appear, complete with formatting and emoticons (if any). You should get into the habit of using it before posting so as to be able to see any typos or mistakes and be able to correct them before posting. This will help you to ensure that your posts are as of high quality as possible.

editing is important when you have low standard in English, but social web sites editing is not importnat, you have to convey the idea.