I kind of agree with you here, man. The revolution ought to use the same democracy, socialism and humanism we want to see in the following society. It makes strategical and ethical sense, and Lenin betraying almost all his old promises once he was in power. But…
Libertarian armies have historically had a bad military track record, I think I hardly need to point to examples. One important detail about this is that every single time, they fought against traditional, hierarcical and usually downright authoritarian armies. I'm sure there are whole encyclopedias explaining why traditional armies always win these battles, but regardless, you can just see how the non-ML experiments fared.
There's a funny thing about the Red Army, when it was created it was exactly like one of those libertarian armies. Volunteer-only, all soldiers were committed revolutionaries, officers were elected, and so on. Problem is, they were nearly worthless at fighting. Maybe such a libertarian army could have been efficient if it had been created and trained properly before combat began, but the situation being what it was, this was a no-go. So Lenin had no choice but to task Trotsky with reforming the Red Army as a traditional army in March 1918, over protests of the first leaders.
This problem with the armies extends to dealing with a restive country as well. I'm afraid that authoritarianism seems to be a necessary evil for the triumph of a revolution. Yes, I know it seems like a paradox: the supposed need to assemble an authoritarian apparatus in order to create a free society runs against the tendency of structures of power not letting go of it, which puts us in luck's hands: we have to hope our dear leader is incorruptible. To paraphrase Lenin: what else is to be done? Look at the trainwreck they were saddled with in the pic.
I honestly think Lenin was the kind of man who would have followed up on dismantling the State; he was a man dedicated to the cause above all else, like a Robespierre or a Washington or the old Roman dictators (a system which, incidentally, worked well for centuries). But as we know, he croaked too soon to finish that task, and lesser men inherited the perfect tool for a tyrant.
Oh my comr8, that's where you're mistaken. More people were guillotined after the Thermidorian Reaction than before. Marx more or less said that counterrevolution would be so much worse than the revolution, that the only way to make both end as soon as possible and wipe away the old order is through terror, as Robespierre was doing. I'm afraid Robespierre didn't send enough people to the guillotine.