How to install an existing Drupal profile with drush? Seems like searching for the answer on Google just leads me to how to create make files and profiles.

I know how to do that.
I also know how to install Drupal with drush.

But I want to install one of the many existing Drupal profiles, like Drupal Commons, Commerce Kick Start, etc. with drush.

I would have thought it would have been just an easy process to find the profile's makefile and run that. Drush will take care of the rest.
But I can't find the repositories where these makefiles sits.

Some direction would be appreciated.
To build on what Patrick said, if the profile is not already in your profile directory, you can download it with Drush dl:

drush dl drupal --drupal-project-rename=drupal
cd drupal
drush dl commons
drush site-install commons --db-url=mysql://user:pwd@localhost/db_name --site-name=Example --account-name=admin --account-pass=pwd

You do not need to run drush make, because drupal.org runs it prior to making the profile available for download.  Thus, when you run drush dl commons, you get all of the components that the Drupal Commons distribution needs to install.