I have two questions about Masonry List View for blogs:
Did you try replacing the 'Masonry Message List' component with the 'articles' component (<component id="articles">)?
Yes @Nava_Schneider, that's because the entire article body is displayed. But you can control the UI to display only the teaser in the blog page with a 'Read More...' link.
Try adding this in the Blog page quilt - <component id="articles" quiltName="BlogMessage"/>