Why do employers and recruiters lie on job ads?

I've done several 1st aid at work courses over the past few years and even in those cases (where reliable and coherent information would seem critical) the tuition has been shoddy, unreliable and confused. It's a good thing that such courses are updated as medical science progresses but the info imparted on a 1 day course needs to be clear enough to be integrated enough to be useful. As it is, if I needed to use this training I fear I would be worse than useless. One trainer we had couldn't help but jump around from topic to topic - "so, with burn injuries we need to remember that burns from a fire are different from electrical or chemical burns, unlike with a cardiac arrest where its really important to..... Oh no I'm talking about burns, so where was I?" ad nauseum for a full day. In the time since I first did any such course I (fortunately) never had to use this training - but this trining has been sporadic enough, chaotic enough and never practised by being real that I'm convinced it's worse than useless. The useful bits I take from it are limited to - the recovery position, and remembering A (airways) B (Breathing) C (circulation), Beyond that my own head will be much more useful and Likewise with lots of other "training". I did a course titled "work based conservation", which tried too hard to be applicable to too wide a range of people, from those just struggling to find work, to those with some serious anger management issues - including someone who angrily stamped on a wildflower whilst telling us all how much he hated flowers because they were "stupid little plant poofs" - on a course with conservation in the name. That same course ended with an assessment using multiple choice questions to stunningly simplistic questions that seemed to have nothing to do with conservation and more to do with basic personal competence and getting along at work with colleagues - I can do that already and don't need such training.