All arms of the Labour 'movement' (including the Co-op, which co-founded the Labour Party) have been smearing and denigrating political opponents since the party's creation. Consider Nye Bevan's characterisation of Conservatives as "lower than vermin." Consider the vicious, misogynistic way in which they spoke of Margaret Thatcher. Consider the constant references to the behaviour of current Cabinet members as young men in the entirely frivolous Bullingdon Club, while laughing off the involvement in their youth of prominent Labour men with the British Communist Party; an organisation actively engaged in treason.
The Labour Party is an organisation founded on hatred and dedicated to expropriation by force (under the euphemism of 'redistribution'). It has no right to complain at full use being made of the exposure of one of its own for what many of them are; hypocrites on the make.