This sucks big time, if true. I am trying to ping Comcast from a middle relay IP address and it seams, to work, I guess you mean AS33651 - Comcast Cable LLC.
The peer's IP address is in ASN 7922, according to whatismyipaddress.com . Note that my test was always opening a TCP4 connection to him using socat. (I know on what port his lightning daemon listens. Obviously not feasible to do such test with a random Comcast customer.) In fact that node does not respond to pings. Perhaps those 2 differences explain different results.
I will send that peer a link to this convo, he could do some tests from inside Comcast's network. He sounded a bit resigned though, so no guarantees obviously.
And thanks for encouragement, up to now my efforts have fallen mostly to deaf ears.