I'm not sure there was a browser that did standards better at the time of IE6's initial release. Maybe Opera.
And in my opinion, the bigger problem with IE6 was that it was buggy -- both where it purportedly followed standards and where it had its own way of doing things, behavior often didn't match spec or had unexpected side effects. It took devs years of trying to figure out where all the bodies were buried before everybody understood how it worked.
There's another side to it too that isn't popular, but IE was in and of itself a standard. When you own 90% of the market, whatever you do is a de facto standard. And I was pretty okay with that up until they decided to stop doing anything innovative with the browser.
And in my opinion, the bigger problem with IE6 was that it was buggy -- both where it purportedly followed standards and where it had its own way of doing things, behavior often didn't match spec or had unexpected side effects. It took devs years of trying to figure out where all the bodies were buried before everybody understood how it worked.