I am enjoying this thread. Please, keep it up!
Both Ryftobuddy and spiderwebz have some points.
I'll be honest and say what I think: trying to bring a discussion about bans and reasonings about its effects to the field of psychology is going out of bounds.
Its 100% psychology when you think about it. Banning someone is form of negative reinforcement with an emphasis on weakening behaviour not strengthening it. There are two kinds, one is strengthen one is weaken.
example -
Weakening - Jane asks to help mum dry dishes, jane drops dish. Mum backhands jane for dropping dish. This teaches Jane "dont help again".
Strengthening - Jane asks to help mum dry dishes, jane drops dish. Mum raises her voice in frustration, then explains to jane that if we drop dishes we can't eat off them. This teaches Jane, help mum but be more careful for you know why.
Banning HonorBuddy is a form of weakening and whilst it seems like they are the good guys in the equation in reality they aren't. There's a wide amount of reasons for botting not just for the pure fun of hacking (which some get kicks out). It's also a supply vs demand equation, and over time its a losing fight for Blizzard if they continue to occupy this position as its been mentioned a number of times in articles/forums etc that have indicated its assumed folks who bot tend to be players of many years. Folks who use gold farms / bots are looking more for a way to bypass the "Grind" to get back to parity with their main toon for things like Raids etc.
So who's at fault? the incentive for playing WoW via grind is low but the behaviour for playing WoW is high. Combine Incentive vs Behaviour matrix and it shows a rapid decay in long-term adoption cycles, its essentially creates a seasonal attitude towards the games and the problem with seasonal experiences is they only work if it adheres to a consistent schedule. WoW has in irregular schedule, resulting in out of cycle adoption(s) for players (ie i could come back to WoW after 2 years during its dead zone - lead up to Legions for example), see population / guild members are offline and think "ok meh, boring, its not as nostalgic as i remember" whilst 2days after Legion it could be an entirely different outcome.
In truth, Blizzard needs to invest in smarter leveling patterns for mature players without imposing a financial hit. Furthermore they should really consider borrowing from EVE in some ways when it comes to skilltrees, in that re-invest in long-term players with years of investment via time focused stat gains - use time played as a skill/stats gain tree aswell.
The game has far too much emphasis on chores and social co-ordination, which means for weekend warriors, Raiding is next to impossible... so there's nothing but psychological issues at play here.