Why do agents send mails like this:

The ideal candidate must have the following skills: SHORT JOB DESCRIPTION.
If you are interested in this position, please respond within 24 hours with a short motivation letter and your CV in Word format so ping-pong can contact you.
ping-pong do have a policy to fulfill job requests within 24 hours therefore a quick response is important.
Sorry, no job description (there was a bit of one at the start but not detailed enough)
Sorry, I'm a contractor not applying for a permanent position therefore a motivational letter is surely not required, especially not for an agency. I'm sure agents know why contractors are contractors...
Sorry, but 24 hours is bollocks.