It will depend on the theme you've used. Right now I'm looking at your blog and going through its CSS coding. When it shows the "Comments are closed", it uses the following CSS:
<div id="comments">
<p class="nocomments">Comments are closed.</p>
</div>
Based on this, you might be able to hide it from showing up on your blog posts/pages by going to the admin side and clicking on "Appearance > Edit CSS." And in the stylesheet editor, add the following CSS:
p.nocomments {display: none;}
Save it, and see if this hides the no comments statement on your pages. The only problem with this is that if you change to a different theme later on, you might have to change this to match the CSS used on the new theme.
Let me know if it works for you! Good luck! :-)