You aren't fighting against Marxist-Leninists, but Marxists, period. The Marxist conception of the withering of the state stems from the Marxist understanding that the base of the state is class struggle, so when you abolish class by collectivizing all production and distribution, you abolish the base of the state, which then gradually withers. It does not mean all administration is abolished, but that the aspects of society meant to certify one class stays at the top no longer need to function and thus become useless institutions over time, fading away like horse-carriages today.