It is a commonly accepted practice that other users should not edit another user's userpage, as it can be viewed rude. Some users might want that one word spelled like that, or the wording of the sentence to be in that order. If you feel that an edit should be made to the page, leave a small note on the user talk page. The user who the message is for might change it, or might leave it the same. Whatever their actions are, you should not edit a userpage.