FWIW, I'm kinda disappointed at how a lot of people here seems to be on your case and downvoting you, when I think the post was quite informative to show how easy it is to acquire usernames from sites, and that maybe companies should rethink the policies.
If it was in isolation, say 'it takes 48 hours to take a username from SoundCloud' then I couldn't care less, but showing it happen on multiple sites and how they address it does make one think.