No, it's not them. I have had that email and information that they are blocking the site since mid-April. It only means that people who use OpenDNS or Umbrella will see a warning message when they try to load the website. It's similar to the red-page Google Safe Browsing warning. You can still bypass it and visit the website if you want. OpenDNS didn't take the site down. It was never in their hands.