Hello lyra, fellow Virginian!
I'd like to tell you, that I am a dumpster diver, and I really enjoy it. I also like to dig through the trash on the street occasionally too, and I have been homeless up until recently. I've eaten half-rotten food, been on welfare, wore raggy clothes, scammed, been all dirty and slept in public places... I am saying this, so that this all is not some big scary foreign "out there" concept - right here is someone who fits the whole disgusting horrible bogey-man that you described. And many of my friends would fit that description as well.
To be honest, it really isn't all that bad. If you have your health, and you're alive, then you've pretty much got it made. One of the worst things about living like that is the fear. For me, it's fear of things not turning out well, of getting hurt, etc. The thing is, with some basic common sense smarts, and keeping your eyes open, and learning from what you can, then you've got a good thing going for you. These fears can be quite intimidating, I know, but the great freedom, spontaneity, discovery, creativity, resourcefulness and adventure more than makes up for it.
You mentioned a number of times that these attitudes are because of how you were raised - all middle class, white, American and sheltered. That's great, I come from the same background too. And I agree, such a background really does a number on one's psyche, sense of awareness and adaptiveness. That being said, once you've noticed that personal response, attitude and background and what-not, then you can work with it. Like, you notice that, then you can go further, beyond even. Take your time with this, this is very important, for not doing so can make the whole thing appear non-sensical and non-existant for you.
For example, you notice those thoughts, the same thoughts that you just typed up all right here. OK, and how do feel in conjunction with those thoughts? Disgusted, repulsed, awe-struck and scared, I presume. OK, and how does that feel in your body then? Only you can answer that... And what does that mean for you? Maybe you're wanting a sense of assurance of safety, dignity and respect? Maybe you're concerned that a kind of consideration and fulfilling self-empowerment is not possible? I don't know, these are all just guesses - only you can unpack your own deeper personal meanings around all of this.
I am saying all of this for a reason, not just to be a contrarian know-it-all. That is, I am hoping to convey a sense of, a possibility of, the fact that what things mean and how they work does not necessarily have to be what it initially appears to you to be. What all this means for other people, and what it means for you too, does not exactly have to be what you first see it as. All your first wave of thoughts and judgements aside, regardless of where they all originally came from, does not necessarily have to be identified with "the way things are". I think that recognizing that, and putting it aside(as opposed to repressing it), can potentially have the effect of removing a veil - and what is seen after that is far more rich, more intricate and full of possibility than what was previously conceived. It is for this hope, that I am talking here.
"Learning of all kinds goes on best, lasts best, and tends to lead itself on more when it grows out of a real focus of interest in the learner." - Carl Rogers