Hillary Clinton's claim to the Democratic nomination on 7 June 2016 was merely a self-aggrandizing and inappropriate gesture. Sanders has maintained he's going on to the convention.
The superdelegates still have to vote, many of whom are running for re-election. They are going to be reminded by Sander's supporters the success of their campaigns depends on their willingness to support Sanders. Every superdelegate's political career is on the line.
To self-declare as the presumptive nominee is also a derisive attempt at "conversation shaping" using the press. It's wrong.
To the Democratic Party leaders: please be patient and wait for the convention before making hasty conclusions. Let the people speak.