Render-blocking JS

When I run a performance test, results suggest a very low score for the resource: "remove render blocking resources". The number is. 27/100.
When I click "improve" the suggestions are to remove render blocking resources. All of the resources begin with http://hb.wpmucdn.com/www.peartreeusa.com/
Similarly, Hummingbird also suggests to optimize "CSS Delivery of..." .
All of those CSS scripts also begin with 'wpmu'
However, none of these assets show up in my file list for assets optimization, and, I've scanned the files a few times. Obviously these are new files place by your software. Can I deactivate the plugin and still use this dashboard? Also, can I still use Hummingbird and SmushPro without this software, if I choose to discontinue the license?