|I suspect the correct way to uninstall this program would have been to first unblock the sites you blocked and then uninstall the application.|
You might try reinstalling the app, check if it still shows those sites as blocked, unblock them and only then uninstall the app. If it doesn't show them as being blocked, block them, then unblock and uninstall.
If none of the above works, or if you'd prefer to do it first, contact the software manufacturer's support and explain your issue to them. They may have a quick/easy fix.
It matters not how straight the gate,
How charged with punishments the scroll,
I am the master of my fate;
I am the captain of my soul.