didn’t immediately solve all problems

I love how liberals constantly downplay shit like this. If you're upset about your friends and family being shoveled into a pointless meat grinder and you're experiencing mass death and oppression, then you're just upset that "democracy didn't immediately solve all problems." In the same way that opposition to genocide is frequently framed as, "throwing a fit because you don't get your way," and such.

It's literally just the Joker speech from The Dark Knight, as long as there's a plan, it's fine, even if the plan is horrible, the only thing that matters is that the norms are respected and the proper procedure is followed. You and everyone you care about can be sent to concentration camps, just so long as the decision is made by a legislative body following proper procedure. Systemic violence, like dragging people from their homes to die in a trench en masse, is perfectly acceptable, just so long as it isn't disruptive, just so long as everything is going according to plan. The only problem y'all have with fascism is that it's so rude and blunt, if it persued the same goals respectfully you'd be completely fine with it.

Yes, it did benefit the people immensely to get out of the war. Aside from the horrors of WWI, with the benefit of hindsight, we can say that if they hadn't dropped out and focused on rebuilding and industrial development at that point, there's a fair chance that they lose to the Nazis in WWII and we'd all be speaking German right now. Besides, in the chaos of this period the so-called "democracy" wasn't some kind of established, functional system, we're talking about a provensional government, and one that completely failed to address ongoing crises (which is kinda the point of having a provisional government). Under the conditions of the time, sensible people radicalize, and then they force things to change and get rid of those conditions, and then people 100 years later to whom the conditions are utterly foreign waggle their fingers about it, but they don't care because they're no longer dying in a ditch.

democracy didn’t immediately solve all problems so we should ban or murder all political opposition

The democratically elected government murdered hundreds of Russians - people who originally supported the government - because they protested the state's continued disastrous warmongering.

The liberals were doing the murdering. The Bolsheviks responded in self defense, often by cajoling infantry into not killing protesting civilians.

This is what brought down the "Democratic" pre-Lenin government. Liberals couldn't order their soldiers to massacre the Bolshevik civilians, so the democratic government fell apart.