Phoenix, from your post I'm not sure whether or not you liked it? Up until like the last paragraph you seemed very cynical. It sounds almost like you went into the movie not wanting to like it and as a result didn't.
But anyway, the main themes behind the movie are as follows:
1) Racism, portrayed in a form that anyone can identify.
2) Xenophobia and discrimination, once again portrayed in an obvious form.
3) Highlighting the existence of stereotypes (the Nigerians, for example, naturally being criminals)
I personally don't believe on questioning technical details behind sci-fi films, as there is so much that is not explained in the film but has no effect on the overall story. I don't think the inclusion of why the ship was hovering there for 20 years would have added anything at all to the story. It's but one of many small details that simply can't all be explained. I'm sure there are reasons behind what Neil decided on. There could be many explanations for why the ship was hovering over Joburg for 20 years, for example. One such explanation could be that considering the alien kid could remotely activate the ship, it was in some sort of standby mode. Another reason could be that since they have tractor beams, they could have some sort of anti-grav technology built into the ship. Who knows, but as I said...all little details as important as when Wikus went to the loo during the storyline.
There's also a few explanations in the movie you have, however, seemed to have missed. One of your questions was why they are keeping the aliens in disgusting conditions in District 9, but transfer them by "the book." In the movie they did mention that activist groups from around the world were keeping a close eye on MNU so that no "human" rights abuses took place. The whole world was watching South Africa, so obviously to avoid an uproar by those on the side of the aliens they had to do everything within legal bounds. Hence the aliens having to "sign" release forms etc.
But anyway, I quite enjoyed it. Not because of the big booms and the special effects, but because as a sci-fi movie it is original. Ignoring what some may see as technical faults, which many movies have, I have yet to see another movie in which the tables are turned and it's the humans abusing the aliens. What I laud the most, however, is how by portraying issues from our country's past and present in such a blatantly obvious manner, it makes them all seem to petty an unnecessary in the bigger scheme of things. The lack of foresight in the humans in the movie (not paying thought to what might happen should the aliens leave and get help, for example), is something that in the past some in our country have lacked. Like we shot ourselves in the foot with Apartheid, so did humankind in District 9.
That's just my 2c
