Basically, what most companies don't like about fresh college graduates is their inexperiences. These companies see them as ill equipped to handle each tasks given to them, as they are yet to learn the nitty gritty of the scope of the business. And at times, they have to use some of their resources in training them to fit into their various job descriptions. These trainings could be in form of internships, probations, graduate trainee programs etc.
Although these fresh graduates are raw talents, but there is still something missing in them. And for them to maximize their potentials, they have to be groomed in accordance with these companies modus operandi. If not, so many losses could be incurred, which would in turn affect the companies capital. And that is what they don't want from these fresh graduates, that's why they are doing the necessary trainings to equip them.