I'm in a chat with a Comcast rep now, who claims that if they were blocking the page there would be a branded error message. There's just nothing. Maybe (hopefully!) this isn't what it looks like.
By the way – the web experience is just that the page hangs. There's no 404, or 'server can't connect' or any other warning message. This type block is indicative of someone throttling the connection to the server. Likely Comcast hasn't outright blocked the site, they've just made the pipe so small that no one can get to it.
The wireshark would show you the TCP three-way handshake successful, then the GET request would go out, get acknowledged, and then nothing.
Judging by the comments on the article it's not Comcast blocking, but some kind of network configuration issue, as multiple ISPs are impacted (though they could in theory be using Comcast as a carrier).
Like I said, it's possible these other ISPS are routing via Comcast, but that's pretty unlikely. More likely is someone has made a config change that's broken the connection for some ISPs.
"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.