Most people read these topics in flat mode (all the posts one after the other), so it is easier to address multiple comments in one post. Place a person's name before a comment, if required.
If you read topics in threaded view, then replying directly to any comments makes sense and keeps related comments together (though this can become disorganized). Unfortunately, this relationship is lost in flat mode (and isn't really required anyway), so multiple replies appear to be attempts to boost post count. Also, multiple short posts are a little harder to read than a single combined post.
