He's pulling a Drumpf, plain and simple.
He's playing on the feelings of the general public and rallying them behind his banner to face 'a great evil' by blowing smoke up everyone's asses. He's charismatic and oppurtunistic, and for him it's a win-win situation to go on the offense. Mark gets to say whatever he wants, publicly, about the current Blizz developers without any backlash. In the eyes of the fans, he can say no wrong because he's championing the legacy servers. If Blizzard says yes, he can secure a position back as developer on Legacy servers. If Blizzard says no, everyone will continue to think it's because Blizzard is being stupid.
There's too many riding the bandwagon to care what he says or does. He's using 'look at all the petition signatures!' to boost his own agenda. This isn't really getting us any closer to Legacy servers.