Your point is well made toybulldog. However, deleting individual posts out of a thread isn’t always as easy as it seems. Fine if there are only one or two of them but if it goes on for several pages – sometimes being ‘quoted’ and sometimes not – it can take a considerable amount of time scrolling back and forth through the thread deleting each post individually.
More often than not, objectionable posts (and objectionable replies) are made when a moderator os offline doing other things and by the time they are spotted …. the ‘damage’ has been done.