Linked to the current call for abstention by some far left members in France, someone twitted (my translation from French): "In 33 German communists refused, them also, to choose between the 'social democrat plague' and the 'Nazi cholera': we know what followed". Looking in Wikipedia, the only election I find in 1933's Germany is the federal election and I find no call for abstention (they got seats) in the election nor could they form a government with more centrists parties (NSDAP formed a government with another nationalist party). I'd like to know what this sentence could refer to.
Although the specific year (1933) is off, the tweet in question as likely referring to the inability of the SPD and the KPD to form together a common popular front against the right-wing attacks against the Republic between 1929-33. Even though both parties were firmly on the left side of the political spectrum and ideologically opposed to the NSDAP, they were institutionally and temperamentally ill-inclined to work together. There was bad blood between the two parties that stretched back to the initial split in the Kaiserreich's SPD during the First World War when the USPD tacked to a more revolutionary form of politics and the SPD instead opted to back a more pragmatic policy of working within the existing system. The USPD eventually gave way to the KPD and during Weimar, it was very much a reflexively opposition party. The political polarization between the German left helped further cement the strength of Hitler's right wing political insurgency. German working class voters began to vote for the NSDAP in alarming numbers over the course of 1931/32, and instead of trying to shore up this eroding support, the KPD and SPD attacked each other, further diminishing the political power of the German left. For example, in addition to attacking the NSDAP and the right, KPD political materials often attacked the SPD as false Marxists and enablers of fascism.
Who was to blame for this lack of a German popular front was the bone of contention among various emigre groups both during the Third Reich and long after. KPD and SED ideologues blamed the SPD's lack of commitment to the working-class as indicative that the SPD's commitment to Marxism was milquetoast and ineffective. Conversely, many SPD leaders attacked the KPD as Moscow's catspaw and so blinded by the promise of revolution and settling scores for the SPD's suppression of the November Revolution that they ignored the danger of Hitler. Neither charge was completely accurate, but both have a certain degree of veracity to them. These antipathies proved to be quite deep and even in exile, the KPD and SPD leadership could not form a common front against Nazism. Amidst these charges and counter-charges one central thread winds its way through is the idea that the German left should have put aside its differences to face an existential threat.