The base-16 output you see is the pretty-printed representation for what is internally just a plain binary!, a sequence of 8-bit bytes:
>> type? read http://www.rebol.com/
== binary!
parse
works just fine with a binary!, so you could just use the result with PARSE straight away.
Alternatively, you can UTF-8 decode the result into a string! via to-string
:
>> type? to-string read http://www.rebol.com/
== string!