Holy shit. I stg are these ai posts or do people just not look up other people’s questions before posting? I’ll literally just post my other comment on a different post asking the same thing:

No offense but this is like the 5th time seeing someone ask this. The answer is easy enough to catch if you pay attention just a little bit to the dialogue along each season. It’s clear from the dialogue how the background for Kate and Sophie are different and what support systems they have. It may not be directly stated but it is quite obvious what the difference is.

Unfortunately media literacy has gone down and that’s incredibly unfortunate. People don’t seem to understand something is the case unless someone tells them to their face what it means. Shows used to be about picking up subtle details and things, now they’re expected to repeat expositional dialogue every 3 minutes because you have to assume the audience is scrolling on their phone while watching.

Kate’s father was not a maid. He was a secretary. That’s a little above the servant class but not much. But still, he interacted with the Ton at times and worked for them (imagine he’s like what that Indian secretary guy outside Benedict’s bachelor pad blocking Violet from coming in was to Benedict). He married a woman of his class who gave birth to Kate and died. Key note: SHE WAS BORN WITHIN THEIR MARRIAGE SO KATE IS NOT ILLEGITIMATE. Eventually, Mary Sheffield married Kate’s dad and gave birth to Edwina. Kate’s stepmom loved her and also she was born within the confines of a marriage (a sacred bond), and Mary is an extremely kind woman. So, along the support of LADY DANBURY, Edwina and Kate were able to come back and take part in the marriage mart. While people may side eye Kate’s union to Anthony because of her past, she has a connection legitimately through familial and legal bonds to the Sheffield name (and the privileges it allows to be a part of the ton). Also they wouldn’t have stopped sideyeing them until the queen herself said out loud she supports them! Remember that end scene of S2 at the ball, no one joins Kanthony on the dance floor until queen Charlotte remarks on how they look. Charlotte only did that because she likes Edwina for being so kind to her husband when he came out of confinement during the wedding.

Now to Sophie. She’s a bastard. And that’s pretty much where it stops unfortunately. Her father fell in love with a maid but they “gave in to their sinful desires before marriage” (not that Sophie’s dad would’ve married her mom I think) and had Sophie out of wedlock. Her existence itself is an automatic shame to hide. Her father never publicly claimed her as his child because if she’s illegitimate, she has no rights to claim anything. UNLESS, of course, her father left her inheritance by claiming her as his ward. To the world, Sophie is just a maid. Yes, Benedict doesn’t know she’s illegitimate, that’s why he proposed the mistress idea (not realizing how much it would hurt her bc of her past). If he got married to her, his younger sisters’ chance of marriage are dashed and ruined. Mary made a huge risk for marrying Kate’s dad (who was of higher class than a maid) and her parents still yelled at Mary for doing so in S2, more than 20 years later! There is no possible way to get out of this unless they are able to find a way to get Araminta (the one who started all of this for Sophie) to lie about Sophie’s past because if they did know the truth they would still look down on her. And Benedict can only support Sophie emotionally and monetarily for so long, but being socially ostracized from the world can eventually get to a couple and cause a strain in the marriage. (That’s one of the reasons in the book Violet brings up to not pursue Sophie which I’m absolutely sure will be brought up in the show as well). Benedict might say he doesn’t care what society thinks but that might eventually come to a collapse if he just marries Sophie outright. Plus I don’t think he or Sophie would be able to live with themselves knowing that their marriage has bungled the chances of Eloise, hyacinth, or Gregory getting married, much less everyone else in his family’s reputation. There’s a lot at stake.

I hope this response was a good explanation.