The bottom line is:
People have to take responsibility for their behaviour.
So, ubisoft promised to the fans to release the MP Demo on Munday and they didn't. And therefore it is not about whining or lamentation, it is the right of everyone to criticize ubisofts behaviour in that matter.
Ubisoft felt sure on its ground and they made a hasty promise they obviously were not able to keep - and that's just not correct! Next time they better keep their mouth shut and release the demo when it's done.