It was disabled at one point, but definitely enabled at the moment in buster at ...

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.