Short answer is that they're nice people, and they understand that power corrupts, so they can't even rationalize wanting to be king of the universe for altruistic reasons.
Also, a post-Singularity future will probably (hopefully) be absolutely fantastic for everyone, so it doesn't matter whether you selfishly get the AI to prefer you or not.
This is for anyone in the LessWrong community who has made at least some effort to read the sequences and follow along, but is still confused on some point, and is perhaps feeling a bit embarrassed. Here, newbies and not-so-newbies are free to ask very basic but still relevant questions with the understanding that the answers are probably somewhere in the sequences. Similarly, LessWrong tends to presume a rather high threshold for understanding science and technology. Relevant questions in those areas are welcome as well. Anyone who chooses to respond should respectfully guide the questioner to a helpful resource, and questioners should be appropriately grateful. Good faith should be presumed on both sides, unless and until it is shown to be absent. If a questioner is not sure whether a question is relevant, ask it, and also ask if it's relevant.