IE9 is a valid browser. You are most correct. In fact it was surprisingly compliant in accepting many web standards that all the way up through IE8 Microsoft had refused to accept. That doesnt change the fact that versions prior were extremely buggy.
I agree that IE should be supported so long as it is a recent version of IE. But IE hate stems from long standing issues with having to support versions of IE long since out dated.. the biggest culprit IE6, who for some reason is still clung to in many technology circles.
Long story short though, if you want your web experience to be up to date you need to use compliant browsers. Its also worth while to have at least two of the 3 major ones (IE, Firefox and Safari), because as much as it would be nice to believe every site will always work the same in every browser, its simply not the case.
I agree that IE should be supported so long as it is a recent version of IE. But IE hate stems from long standing issues with having to support versions of IE long since out dated.. the biggest culprit IE6, who for some reason is still clung to in many technology circles.
Long story short though, if you want your web experience to be up to date you need to use compliant browsers. Its also worth while to have at least two of the 3 major ones (IE, Firefox and Safari), because as much as it would be nice to believe every site will always work the same in every browser, its simply not the case.