Y'all

I can see that people are angry/dissapointed at Cain and with everyone around the MC and their sociopathic behaviors but I really want to emphasize, the story isn't based on modern common sense of fellowship and human rights, it has references to historical nobility circles/ aristocracy. The story has mentioned it already, the Duke chose the previous MC because her behavior and poor family standing is ideal politically and internally (matters of the house). He basically took her in as a tool and while he gave her some freedom in his head (that if she ever requested him something or wanted to speak of something they can talk about it), he also wouldn't care enough if she was coward enough to not say it. He just needed someone stuffed into the position, she was the type of chess piece where no matter what happened to her it wouldn't pose any problems at all. This notion just worked wonders among all the servants in a prestigious powerful noble house when the new mistress is as incompetent and cowardly as her social standing (not her duchess seat because everyone vaguely knows the intentions of the master, looking at it politically) implied.

I do think the harrasment is quite exaggerated (like really exaggerated in a sense, the maid's and other worker's actions specifically) in the webtoon, but Cain's attitude is about right. He's the closest servant to the Duke as head butler, he's clear on the position of the mistress. Also being a high ranking nobility's close aide, he's dealt and seen things as it's the privilege of a powerful household so he can't have a disposition like those warm family butlers. He just basically adopted the attitude of his master towards the issue. And personally, serving an ambitious and powerful master, he's bound to disdain the MC especially since he knew the Duke's thoughts and how in reality the duchess is below dissapointing in manner and personality.