the author dismisses the assertion that most men aren’t violent by asserting that they are “programmed from birth” to be violent, and as such the fact that they haven’t been is no reason to not treat them as if they had been.

I think it is fairly clear that bell hooks is talking about external gendered expectations not any sort of biological essentialism.

As for the expectation of violence in media

I really don't think it's about media. Nor do I think the current state of on-screen violence is nearly as impactful to the adults of today. This sort of thing get's ingrained during childhood and while of course individuals are always changing, childhood exposure while you are still building your model of the world is unique. The current state of affairs will tell us far more about tomorrow's men than today's.

All that said I don't think you need to look to media to see this phenomena. If you've ever walked a female friend or partner home, you've probably experienced these pressures. You may have taken them in stride as many are happy to fit those gendered expectations (most folks are very much willing to dish out the good violence) but there is a real sense in which those expectations are both unfair and contributing to a larger sense of violence as a necessity. For so long as we are discussing the right kinds of violence for masculine individuals to enact we are making assumptions about the intrinsic violence of masculinity.