While I don't personally believe that you should be readying your child for kindergarten as though they're heading off to middle school, already knowing how to play the violin and having medals in fencing. Kids should be kids for as long as they can, and there's a lot of time in their future to excel and overachieve.
However, it is very important that your child isn't totally shell-shocked when they arrive on their first day of kindergarten. Some of these items signal readiness for kindergarten, and others are simply good practice to get your child ready to spend the day without you.
And think of it this way: If parents haven't taught their kids how to use the bathroom on their own, button their own pants, and wash their hands, you can bet the teacher won't have much time to actually teach after helping all those little kids pee all day long!