I cant tell you how many job postings I read that said things like you need 5 years experience with X,Y, and Z.... only problem is Y and Z have only been out for 2 years and 4 years respectively.
And guess what? Somebody still applied for and got that job. You have to understand how the hiring process works at a lot of companies. The process of applying for jobs is essentially a sales job - you are selling yourself. A clueless job posting like that might make you think "I'm not going to work for these idiots" or you might see the opportunity it presents. It's really a job posting that is going to have fewer applicants.
The company I work for has a really hard time hiring developers. You would be shocked at the number of people who have a degree in computer science who don't know how to program. After reading about it on Jeff Atwood's blog, I've given a few applicants the fizz-buzz problem and the results were very depressing. Probably 25% couldn't code the answer or write out pseudo code on a whiteboard.