Why bother with performing edits and customized redactions and renames when it's easier to simply delete the comments or accounts?

Because there's value in preserving history and this value grows as the site ages.

This thread has been a bit of an eye opener for me in terms of community management and engagement. Bravo!

The worst thing about browsing old Reddit threads is when half the discussion has simply disappeared because the user hates Reddit and edited/deleted all their comments. There's an awful lot of information lost there, and sometimes it's extremely difficult to find elsewhere. The same goes for the occasional deleted accounts and posts I've seen on other forums around the web by people the forum administrator have deemed "toxic" and purged posts instead of simply banning the user (I only have a single vague memory of a forum other than Reddit where a user voluntarily removed all of their own posts, likely due to the difficulty of doing so).