Oh, we know what happened and why. It's been stated over and over.
Malone was off to the hot start against a super-difficult schedule playing the bruising style that best fit personnel. Mullin and PDA didn't agree with it and Mullin wanted to coach. Malone didn't put up with their interfering BS, so PDA and Malone eventually weren't talking much (if at all). So as soon as the team floundered with Cousins out sick, PDA and Mullin got Vivek to fire Malone thinking that they could keep the team floating with Corbin until the offseason, where an "exhaustive" coaching search would lead to Mullin. He wanted to coach, but apparently only if he had an offseason to prepare and go through training camp.
They completely missed that the team (and fans, so a large extent anyways) had bonded with Malone in a way they couldn't anticipate (his no-nonsense fighting attitude, defense first mindset, and clear way of addressing issues) and the fact that Corbin was in no way capable of coaching this team after Malone had taken it to where we were at that time. These were OBVIOUS to anyone with a pulse, as seen by the reaction of the fanbase when the firing occurred. They were just clueless. Actually, had they fired him in the offseason after another 28-win year I doubt there would have been that much of a fuss. Especially if they had hired Karl.
They only reached out to Karl when Mullin refused to take over mid-season and the losses were piling up like snow in a blizzard and the fans revolting in social media (and, likely more importantly, season ticket sales deadlines approaching). I know I was being respectful online while expressing my displeasure and I was blocked from Vivek and Leslie on twitter, for example. And I wasn't the only one, by far!
So you can look for deeper meaning in all this if you like, but the reality is this was basically a power struggle with Mullin and PDA triumphing over Malone, but the results have been CATASTROPHIC. Hence, the venom.