Didn't Google give up on IE6 for some of their services when it had less than 20% market share? Opera has 1-2% market share. Granted, it should be a lot easier to tweak their code for Opera, but the difference in market share is pretty big, too.
>Granted, it should be a lot easier to tweak their code for Opera
In fact, most things would just work in Opera as they do in the other browser if there weren't any Opera-specific sniffing code in place locking Opera out.
Even MS wanted IE6 dead. In this case, it is all about Google trying to force a very good browser that has brought in great ideas and features, in addition to the performance and standards compliance, out of the market.