Honestly, I've felt this way for a long time, even before I got into home brewing. If you've ever actually stuck your head inside a dishwasher a few days after a wash, you will smell organic matter. There are just too many nooks and crannies where food particle can find their way into, rather than just the drain. And some of the rubber/plastic coating the tines and all the racking can become cut or busted over time, again leaving little places where biomatter will hide.
If you read the literature on IIRC starsan they even say the you have to be clean before you can sanitize, if there's a deep scratch in for example your bucket and there's biomatter present in the scratch it even says that starsan will not sanitize that....
I know a lot of folks think it's a good idea to sanitize in the dish washer, but I've always thought they were just big breeding grounds for nasties- just too complex inside. Too many places that can't be totally cleaned out...Not matter if the antibacterial cycle is being used, I bet the top and bottom four corners of the interior don't totally get hit with enough water to actually kill all.
That's my take on it. I've never recommended it, but if folks feel comfortable risking it, that's their perogative, but I'm sticking with a no=rinse sanitizer.