A study done in 1953 showed that of the 42,000 people who had survived the Buchenwald concentration camp, only 700 were entitled to compensation under the 1953 law. The German historian Alf Lüdtke wrote that the decision to deny that the Roma and the Sinti had been victims of National Socialist racism and to exclude the Roma and Sinti from compensation under the grounds that they were all "criminals" reflected the same anti-Gypsy racism that made them the target of persecution and genocide during the National Socialist era. The cause of the Roma and Sinti excited so little public interest that it was not until 1979 that a group was founded to lobby for compensation for the Roma and the Sinti survivors. Communist concentration camp survivors were excluded from compensation under the grounds that in 1933 the KPD had been seeking "violent domination" by working for a Communist revolution, and thus the banning of the KPD and the subsequent repression of the Communists were justified. In 1956, the law was amended to allow Communist concentration camp survivors to collect compensation provided that they had not been associated with Communist causes after 1945, but as almost all the surviving Communists belonged to the Union of Persecutees of the Nazi Regime, which had been banned in 1951 by the Hamburg government as a Communist front organisation, the new law did not help many of the KPD survivors. Compensation started to be paid to most Communist survivors regardless if they had belonged to the VVN or not following a 1967 court ruling, through the same court ruling had excluded those Communists who had "actively" fought the constitutional order after the banning of the KPD again in 1956. Only in the 1980s were demands made mostly from members of the SPD, FDP and above all the Green parties that the Federal Republic pay compensation to the Roma, Sinti, gay, homeless and "Asoziale" survivors of the concentration camps.