Yeah Dempsey was ruthless those beat downs were brutal, but it was the nature of the sport back then. Not only public outrage but also due to the mafia and organised crime boss's, it would get to a stage where the police would stop the fight at times when they saw what was going on but the damage would have already been done, police stoppages were also common during the early 20th century when fights were scheduled for an unlimited number of rounds :/ scary to imagine that.
That stoppage involving AJ/Takam was shady as hell, Takam had a cut but he was moving his head so well, AJ was missing everything he threw and had gassed completely at that point, Takam looked the fresher of the two and he deserved to continue, he was starting come on stronger. If you watch many of AJ's fights you'd find that majority of them were TKO's as well referee stoppages, not saying they weren't justified but quiet a few have been questionable; it's not hard to see what has been going on and more recently emphasised in his last fight.
The Ray/Mancini fight was a big turning point, purists were still angry in the aftermath but credit to the governing bodies to an extent for pushing 12 round contests although they were motivated by $$$$ as well because broadcasting networks found the shorter contests more marketable to air live.
Watching that video just makes you appreciate those Heavyweights of old and what it meant to be lineal champion, these days a guy like AJ knocks a few bums over and people deem him the best but he does not hold the lineal title which is not easy to attain and it can only be earned, in unique circumstances you may not be required to beat the man who beat the man due to a retirement or in the case of an Adonis Stevenson who has avoided top 10 fighters for 2 years and keeps paying his mandatory's step aside fees lol he was stripped by The Ring although TBRB still recognise him as the lineal LHW, I appreciate their rigidity but in this instance they need to address the unique situation, The Ring's policy accounts for such circumstances in their lineal championship policy; they are not perfect in that they are too flexible at times while TBRB are too rigid, however if you hold either titles you deserve to be the undisputed champion in your division and more often then not, when a Ring title is won, the TBRB title is won simultaneously as we saw when Tyson Fury dethroned Wladmir Klitchko.