I'll just say it - the guy is being a jerk. You hired these people and want to see them succeed. They signed on partly because of their experience with YOU. Of course this is upsetting! I'm mad just hearing about it.He is doing this to my new hires as he trains them. It is de-motivating for them. I had one ask if he was fired he did so poorly. It's just not helpful.
In social encounters people use these tactics as ice breakers to cover their insecurity. One goes away with, "Yup, that guy's a jerk." But this is abusive in an employment situation. He is using his status as a superior to get over on others. This is not helpful to the company or the employees. Hopefully this is not the culture there? Are you the exception? The trainees may be now forewarned and should get out while they can, or hope to be in a different department. Maybe you have an employment handbook that covers this? Some guys never get over grammar school. You know the saying people get promoted to their level of incompetence? Proven here.

I think this is Hazel at two weeks, her wings were much less spotty and barred and she had a deep brown blush in her chick down. I almost named her Caramel, but her full name is actually Hazelnut.