In more general terms, the question of "how do you teach?" comes down to thinking about what's important and interesting to the person doing the learning. When kids' interests happen to line up with parents', then any kind of parenting looks good. When they don't, whether it's considered good or bad parenting comes down to how much what you do looks like what everyone else does. If you look just like you're neighbors, then you have a rotten kid. If you don't, you're a rotten mom. That's the way public opinion works.
The reason you get such a mix of parenting stories, with some looking like success and some "failure" is because what's important and interesting to individual people (children) will be different at different times and in different ways. When teaching (including modeling) lines up with learning, it looks like teaching works. When it doesn't... well, that's practically the definition of "bad kid".
Courtesy, or the outward show of "respect" is a complicated song and dance. That's important. Some people do it easily - we all have natural aptitudes! Some don't. It helps to think about all the various components of courtesy: word choice, body language, eye contact, tone of voice, inflection, pacing of words, sense of timing. To a lot of people (children) it Feels like an act - to some it feels fundamentally dishonest, which is why you get words like "authenticity" and movements like "radical honesty". Courtesy and respect can feel like a great big lie that other people require of you. And for a child, who's probably also being told that lying is wrong, that's a gigantic mixed message. Tell the truth, but never about what you really want and think and feel, especially when it's something adults don't want to hear.
Think about "back talk" in terms of honesty for a bit - your kid is being authentic with you, telling you what she really thinks and feels. She disagrees with you and isn't candy coating that with sweet words and tone. Maybe she isn't doing that because the song and dance seems like a big fake in the moment. Maybe it's just a whole lot of work, work that she can't quite manage when she's distracted or stressed in some way (hungry, tired, frustrated, excited, etc). In a very real way, she's being incredibly respectful of you as a human being, because she's letting you know what's important and interesting to her in the moment. She's just doing the performance wrong.
As a parent, that means that it's up to you to decide when that performance is more valuable than your kids' honesty. That's a big ethical dilemma! Over time, kids do learn social skills from people they care about because human beings are social in nature. We like to be nice, we like to have friends, we like to smooth our own ways. When kids aren't bombarded with nos and don'ts about things that don't make sense to them, they tend to develop a better understanding of the rationale behind courtesy rather than just a bunch of rules about the performance. But depending on the social environment you live in, it may not be feasible or safe for your child to be honest. It may be necessary to require them to perform some of the time.
So, you look for ways to make it easier on them. You apologize for not being able to accept their honesty in every given moment and offer alternatives: "yes, I want to hear your story, but later, sweetie." You look for ways to keep your kid out of situations they can't handle - where they won't able to perform because it's too hard for them. You look for lower key situations where your kid can practice some parts of that performance. You Create those situations by being patient with your child's honesty and continue modeling courtesy. You offer up hints and coaching when it seems appropriate. You perform for your child and gently deflect criticism so their learning process isn't derailed.
It's frustrating, as a parent, to have the socially gauche kid, the one who can't just fake compliance and cheer like Little Miss Sunshine next door. I've never had "good" children in that sense... but I also didn't start out unschooling so I know that I wouldn't have gotten "good" children the old fashioned way, either. They don't all come that way. What I have seen, though, is how, over time, kids have reasons to want to connect with people and will learn the skills that make that easier when they can. I've seen my wild, impossible child grow into someone who moves easily between a variety of cultural groups because he's had the chance to learn to understand courtesy and respect on a gut level that shows even when he doesn't have the exact right words or mannerisms. I've seen my super-introverted don't-look-at-me child give thoughtful information to emergency professionals in such a way that they saw her as solemn and sympathetic, rather than sullen and disrespectful.
None of that would have come from "teaching respect" because my kids don't appreciate being taught, and have let me know that pretty clearly. It has come from time and maturity, and chances to learn in ways that are meaningful to them.
Something else that's worth keeping in mind on the topic of respect/courtesy is that homeschooled kids often learn more adult social skills from an early age. That can make them seem weird - it's part of the stereotype of the oddball homeschooler. It can also make them seem disrespectful because they're approaching adults with the same level of respect and courtesy that adults give to each other.
There's a big power dynamic between adults and children - children are, in a sense, a "lower class" and it comes out really, really starkly on the subject of courtesy and respect. It gets rationalized in terms of "they have to perform in order to learn" but that doesn't account for the degree to which adults feel resentment when kids don't do the things we expect from our lessers. We expect our lessers to comply, to smile at us, to conceal their true feelings in preference for ours, to stroke our egos. That's a big part of what it means to show "respect". It's not about actually respecting another human being in the sense of giving a hoot, it's about demonstrating that you know your place.
And depending on the circumstances of your life, showing that you "know your place" might be pretty important... although there are different trains of thought on that subject even among adults. It can help to remember that there really isn't single rule for when it's better to keep your head down and when to stand up and say, "no way, fuck this noise, I am as human as you are." Insisting that our kids always "show respect" doesn't offer them the true complexity of adult life where sometimes doing the "right thing" is the wrongest choice of all.