Hmm, ok so you suggest all of a sudden switching to explicitly calling Python 2 with python2, like it is now for Python 3? Python 3 is present and working by default but we just decide, by convention, that Python 2 = python and Python 3 is python3. For obvious backwards and horizontal compatibility.

  $ lsb_release -a
  No LSB modules are available.
  Distributor ID: Ubuntu
  Description:    Ubuntu 16.04.1 LTS
  Release:        16.04
  Codename:       xenial

  $python3 --version
  Python 3.5.2

Edit: Just to check I started a clean 16.04 (on DO) and did the commands:

  # lsb_release -a
  No LSB modules are available.
  Distributor ID: Ubuntu
  Description:    Ubuntu 16.04.1 LTS
  Release:        16.04
  Codename:       xenial

  # python --version
  The program 'python' can be found in the following packages:
   * python-minimal
   * python3
  Try: apt install <selected package>

  # python3 --version
  Python 3.5.2

So, no python 2 by default but python 3 and you call it using "python3" as adviced in the pep qznc talks about.