> Parler had 10 million users, equivalent to more than 4000 subs, not one.
That's about 1/3 the size of /r/askreddit, and comparable to /r/politics. Your approach to the math here is silly for a variety of reasons (users can be members of multiple subs, membership isn't split evenly among all subreddits, there's a long tail of subs with 1 or 2 members, etc.) Parler was equivalent to a mid to large subreddit. It would have been around the 50th largest.
/r/politics, for comparison, has a moderation team of ~60, most of whom have years of experience moderating the subreddit, and is assisted by a number of bots (automoderator, as well as some /r/politics specific bots) developed and tuned over the years to help. They also have direct lines to the admins (most major subreddits do) for when they need more official assistance. The sub also has a fairly well understood set of rules, and users who are willing to report offending content.
Parler had none of those things. I've had the pleasure of moderating a (much, much!) smaller community. I once encountered a situation where it got viral for a very controversial reason. I and the rest of my moderation team was unable to keep up with the quantity of content being posted, so we did something very simple: we locked the subreddit temporarily, preventing anyone without a history in the community from participating.
I stand by that decision having been the responsible thing to do. I can understand why, for profit reasons, Parler didn't want to do the same thing, but it would have been the responsible thing to do.
> "Nuke from orbit" against something that had the capacity to be saved through measures dramatically less drastic than that.
I've yet to see any evidence that this was the case. "Saving it" in the way Amazon wanted seems to be entirely anthitetical to the approaches Parler was willing to take. Even now, the best approach Parler has been able to come up with is to use some AWS ML scanner to detect bad content.