As has already been suggested, the courses don't make any difference to some people's behaviour. However you could say exactly the same thing about courses for sex offenders, domestic violence abusers, et al.
Such courses are never going to be 100% effective but, if they help to reduce the numbers of abused children and women (as well as some men) in our country, they've got to be worth trying.
Similarly, if driver awareness courses only get some people to drive more safely, that's better than having everyone who breaks the speed limit (etc) carrying on as before with their driving habits.