[2] does not support the idea that white noise causes autism. It's a pretty big leap from "freeway proximity, even in utero, correlates with autism" to "white noise causes autism."
edit/ Having said that, the "white noise" machines that I've seen, which are available as sleep aides specifically for young children, are not really white noise. There is white noise there but there is also something that sounds like a tumbling drying machine, or a fan, or a hair dryer... Something that a brain could attach itself to as a pattern.