For social democrats, Marxism was ideology, not practical program.

Evidence

When Grünberg professed his Marxism, it was thus a profession of Social Democracy. Marxism served the Social Democrats as an ideology, in contrast with their practical activities, which never went beyond the boundaries of middle-class social reformism. — Rolf Wiggershaus, The Frankfurt School, 104

Categorization

• XREF: Connects to the long-standing critique of Social Democracy as reformism in disguise, echoed in Lukács and later critical theory. — connects to: Wright retained Marxism as method while rejecting it as ideology — Cedric J. Robinson, Black Marxism_ The Making of the Black…, 1421; German Social Democrats were intellectually Marxist yet programmatically Ricardian in economics — Mark Blyth, Austerity: The History of a Dangerous…, 529; Weimar-era liberal opinion tolerated Marxism as theory while condemning its practice — Rolf Wiggershaus, The Frankfurt School: Its History,…, 124

Broader Connections

• Wright retained Marxism as method while rejecting it as ideology #qualifies (0.85) — Cedric J. Robinson, Black Marxism_ The Making of the Black…, 1421
• Weimar-era liberal opinion tolerated Marxism as theory while condemning its practice #epitomizes (0.82) — Rolf Wiggershaus, The Frankfurt School, 124
• German Social Democrats were intellectually Marxist yet programmatically Ricardian in economics #corroborates (0.80) — Mark Blyth, Austerity, 529