> the decompression algorithm, i.e. the route from the genome to brain, is insanely complex, but it doesn't say anything about the actual complexity of the brain

This is where both Kurzweil and you are wrong. A very complex compression/decompression scheme can achieve much better compression. Intuitively, you can encode some of the information in the decompressor itself, even if it is in a very abstract form. This is the reason why compression competitions include size of the decompressor code, e.g. http://prize.hutter1.net/