It was disabled at one point, but definitely enabled at the moment in buster at least (try docker run -it debian:buster-slim /bin/bash if you don’t have Debian at hand).

Looking at https://sources.debian.org/src/bash/5.0-4/debian/changelog/#...,

  bash (4.0-5) unstable; urgency=low
  
    * Re-add dependency on dash, lost with the upload of 4.0.
    * Don't configure with --disable-net-redirections.
    * Fix name of system wide bash_logout in bash(1). Closes: #546200.
    * Stop shipping the sh and sh(1) symlinks. Closes: #545103.
    * Apply upstream patches 029 - 033.
  
   -- Matthias Klose <doko@debian.org>  Sun, 13 Sep 2009 12:55:54 +0200

it seems net-redirections has been reenabled more than a decade ago.

Using Debian 9.0 "Stretch" derived Bunsen Helium. Its enabled.