Well I'm loath to interpret something for you, so I won't do that. But in the interest of answering your question, I'll try to be brief, since the conversation could go on for a while. Before that, though, the fact you had such an intense reaction to it to me suggests an important part of the power of the film and the maker's intent.

Many people at the time it was released were sort of blissfully unaware of this type of of life--the 'soft-whte underbelly' type of story--that exists in many places in America. The meandering, near-pointless storyline reflects the lives of the characters, who seem to be trudging along in a desolate existence, destined to go essentially nowhere. All the choices he made with the film seem to reflect that for me. And it was done in a way that wasn't really attempted in a film which had some minimal aspiration at reaching a mainstream audience.

Within and beyond that, it's all personal interpretation; and I would not equate appreciation with enjoyment. One can feel complete horror at the sight of something new, and have that register as a valid and even edifying experience. Or recognize a droning storyline as an appropriate artistic choice. These are forms of "appreciation".

Now, onto my curiosity: how would you describe the "kind of people" you know who appreciated this movie?