It is nice to see people passionate about this, but this is NOT apple's fault at all. Safari 3 is 100% standards compliant, however FF2 is not, (FF3 I think is, but it is still in beta). The responsibility falls on the developer of the website who cant make their web site compliant with standards (yahoo)!
So saying safari is obsolete is inaccurate, since it supports standards more than any other stable browsers (other than opera). Apple has done all that they can to offer a good development environment for web developers. As a web developer I have to say safari is VERY easy to develop for.
it has nothing to do with "rights" it has to do with yahoo writing decent code.
Look at it this way, when I make a website, I dont tell Apple to make safari work on my site, I make my site work on safari (which most of the time isn't hard at all, compared to IE and FF, as safari is very forgiving!), and then I make it work with FF and IE!
send your complaints to yahoo, as it is 100% their responsibility.