PHP DateTime ISO 8601 is a liar

http://php.net/manual/en/class.datetime.php says about DateTime:ISO8601:

Note: This format is not compatible with ISO-8601, but is left this way for backward compatibility reasons. Use DateTime::ATOM orDATE_ATOM for compatibility with ISO-8601 instead.

Screen Shot 2016-07-28 at 11.32.18 AM

Ha! Why did you call it ISO-8601 then!