Comcast are denying deliberately blocking it, from their Twitter customer support team:
"We don't block websites. But did escalate and looking into it"
"We don't block websites. But did escalate and looking into it"
I worked for AT&T and was regularly left in the dark, finding out later on that what I was told to say was in fact not the truth. I'm not putting on a tin foil hat just yet, but I'm suspicious.