Honestly, there's not a huge amount of difference between

  <a href="#" id="show-help-link">Show Help</a>
  <script src="text/javascript">
    $("#show-help-link").click(function() { showHelp(); } );
  </script>

And

  <a href="#" ng-click="showHelp()">Show Help</a>

I mean, HTML has behavior in it. A link in itself is "behavior": when you click this tag, go to the page defined in the src attribute. So, as the author says, it's not really a bad thing that templates have behavior in them. In Ember.js, for example, you have an {{action}} handler that is essentially the same as ng-click - "run a function on the controller when this is clicked."