You are correct in that Trudeau opposed Harper's omnibus bills, but you have to remember, Harper and the Conservatives were never, ever, suppose to govern, only the Liberals were and, therefore, as the natural governing party, everything they do is holy and correct.
Just maybe Justin should have spent a little time looking at the consequences of his promises, but there was an election to be won and campaign promises have nothing to do with governing. 
I am just loving the hypocrisy of the Liberals, but I am also amazed at how their apologists can't see the hypocrisy.  It is like they have blinders on.  I even have a friend who is member of the LPO who still thinks Wynne is doing a good job.  He is just blind to the damage she has done to Ontario.