The ALT parses is not added to the default formatter because the alternate formats will never get called.  The formatter only moves to the next when it fails to parse the String.
Ex. if we have two parsers in the following order, in or formatter
parser 1 format "dd/MM/yyyy"
parser 2 format "MM/dd/yyyy"
And we try to format the String "04/24/2014" the following will happen.
Parser1 will be able to parse the format, but it will throw an InvalidArgumentException when it tries to assign 24 as a month of the year.  This exception causes the formatter to not try to parse with the second parser.

So to get around situations like this, have put a default parser which should always have international formats for the dates (the day before the months, etc) and an alternative formatter that contains US date formats regarding months and day order.  If the international version throws an exception, then the Alternative formatter is used.

I tried to make the comments reflect this, obviously I did not make this clear enough.  Any direction on what should be added to the comments to make this clear would be helpful.