There are even websites fully dedicated on correcting (naming and shaming) w3schools, like http://w3fools.com/
About half the items on that w3fools page seemed like nitpicking … but the other half had some whoppers. And hey I learned about the google blacklist in the bargain, no need for a greasemonkey extension, so that was cool too.
I agree with you, but we’re talking about a whopping huge pile of nitpicks. So many tiny flaws still makes for a pretty useless information source to me.
I wouldn’t mind it much, but this has been going on for so long now and I see little effort to better the website given the whopping amount of information available to be able to do so - they don’t even have to think about it really, just spoon over what other people have already written down for them 
That is the biggest fail in the whole story to me.
So i possibly have to change my mind about w3schools after all. 
Reading the Posts and the information bits around the code on w3schools proofes to be a bit frustrating.
Still i’m missing a how to at the bottom of the majority of the how not to sections. They do describe whats wrong. But not how to make it right. Some code-snippets would sometimes be nice.