The problem is with the Shoutcast server at least, possibly with some other servers as well.
I think the source of the problem is this: https://trac.webkit.org/changeset/201895/trunk/Source
Shoutcast stream doesn't have HTTP headers, and because of that it is interpreted as HTTP/0.9 running on the non-default port. So for example jPlayer request for the stream, will be immediately shut down. The problem came to light with the macOS "Sierra" release. On on macOS "Sierra" any stream on shoutcast.com doesn't seem to work.
See also: https://github.com/happyworm/jPlayer/issues/380
Was this expected?
This is being tracked internally by Apple as <rdar://problem/28734311>. It's not quite clear yet if the fix would be in WebKit, or in system libraries below it.
(In reply to comment #2)
Disregard this comment.
As a way to ameliorate the effects of bug #158589, filed bug #164530 to allow an Shoutcast/Icecast stream served over a default port (e.g. 80).
Daniel, as mentioned in my comment on the bug you raised, the proposed solution is inadequate. https://bugs.webkit.org/show_bug.cgi?id=164530#c7 explains why.