Why http proxy being ignored by yum for Red Hat Satellite 5?

Issue

• Why http proxy being ignored by yum for Red Hat Satellite 5?

• Using yum and yum-rhn-plugin, timeouts doing updates or getting repository lists from Red Hat Satellite.
  yum strace shows connect() call trying to connect directly to Red Hat Satellite server, which is only allowed to be accessed through a proxy.

  # yum update
  [...]
  failed to retrieve repodata/repomd.xml from rhel-x86_64-server-7  error was [Errno 14] curl#7 - "Failed connect to ((satellite)):443; No route to host"