It's a test case I wouldn't read too much into it. Maybe it's evidence of a massive anti-trust conspiracy at google, but it could very well be because it's the first domain that came to the programmer's mind at the time.
There's no smoking gun here, but I don't think that concern might be dismissed out of hand. It might be good to see what Yahoo's take on this. This could even evolve into participation by the US Attorney General. I'd like to know more, either way. Like if Yahoo was independently added to the list at a later date, or if it was there from the start?