Snapedom

I think that with the heavy hinting that JKR gives that Severus came from an abusive home, it would be unlikely for him to repeat those same actions. While I know that like 1/3 of abused children go on to abuse their own children, I think that Severus very consciously made an effort to separate himself from his father, his "muggle" side, even going so far as to take up the pseudonym with his mother's maiden name. I think he was very aware that his treatment at home was wrong, and I don't think he would be inclined to use violent actions toward children (or anyone who wasn't actively attacking him, for that matter. One of the few times we see him use actual violence is when he casts Sectumsempra on James in the OWLs incident.)

I think that he had a lot of bad treatment in his life from a lot of directions, and while he did mimic some of them as an adult (the bullying mostly, I think it was a very learned behavior on his part - it seems the male figures in his life at home and the "approved" and respected males in school all employed these techniques), but unlike the actions by James & Sirius which were applauded and enjoyed, I don't think he would have ever been given the impression that the violence he likely experienced verbally and possibly physically at home were appropriate. I also think that his experiences through the Death Eaters would have brought violence more to the forefront of his mind. As a very young man I think he was in love with the idea of the Death Eaters, but he was obviously pushed away from them and became aware (if he wasn't before) that such actions are wrong. No matter what Harry thinks, Severus is clearly following an internal moral code of his own, and so I was shocked to see him show that kind of casual violence in the movies and felt it was ooc for him.

However, I don't accept the movies as canon. They're a different fandom, in my mind, the characters are all different. (Compare the Rons. I mean, really?)