Because the CDU is changing the electoral law and the composition of the districts - and against a citizens' vote:
The SPD, GAL, and the initiative "More Democracy" reacted with outrage to the Union's plans, which can be decided by a simple majority in the Bürgerschaft. The vote of the Hamburg citizens in the referendum had been clear, said SPD state chairman Mathias Petersen. The SPD interior expert Andreas Dressel spoke of a "renewed moral breach of the constitution". Referendums were apparently only followed, "when the gentlemen Beust and Fischer have no objections". The Senate had already sold the municipal clinics against the will of a referendum at the turn of the year.
Power is more important than democracy and the will of the citizens. Here one coalitions with the right-wing scum or simply tramples on democratic decisions, as one pleases ...