Gerard Jones believes that holding a child back from violence could result deadly. Shielding the bad from developing children will not only instill more fear but create confusion. Jones had mentioned when growing up "I suffocated my deepest fears and desires under a nice-boy persona", this leading to not very good or a healthy imagination. When introduced to comic books, Jones found freedom and leadership from the superheros. His favorite character was the Hulk. In his 30's Jones wrote action movies, and even some Hulk stories. He had become greatly successful in this superhero genre. Jones had mentioned "I'm not going to argue that violent entertainment is harmless. I think it has helped inspire some people to real-life violence". He was a strong believer that violence was healthy for the mind.
In my belief, I agree that when shielding violence it only would be for the worse. When you can accept the violence especially with superheros, it usually has a happy ending. Or at least a great battle. Watching violence and the outcome can almost reassure you that everything can be okay or will be okay.
The fact that King Solomons Mines was written for the adventure boy genre, it was their "comic book violence relief" at the time. Haggard made the book pretty violent for the young boys. I'm sure that this was very accepted at the time and definitely built character in the boys. Watching Quatermain be a man, surely was inspiring for the children. It was relatable and was their relief and fix of violence. Quatermain was their superhero of the time.