Question: why do left-wing French posters seem to hate PS so much?
Because gay marriage is pretty much the only thing in their program they accomplished?
Rest of term was liberal reforms to appease Merkel/employer association/EU/"increase competivity".
Their European policy is also pretty much always side with Merkel and berate Italy for trying to organise a left-wing alternative. Also, endorsing ND over SYRIZA and complaning about the "unstable" left-wing coalition in Portugal.
And now, they want to authorize a permanent state of emergency and lower civil liberties (allowing raids without warrants, among other things) because "Charlie Hebdo and Bataclan". Also, they used the anti-terrorist legislation (passed after November events) to do raids and arrest people in ecologist organisations opposing expropriations and construction of a big airport in Nantes. Also, they pretty much tried to ban all demonstrations, because "national security".
Really, I don't see why left-wingers would be annoyed.
I
In their defence, this is a moderation of the PS' historic position towards angry greenies.