True Christians don't follow any of the commands of the OT unless they were repeated in the NT that superseded it (Heb 8:7,13).
In fact, no Gentile was ever expected to follow the OT as it was a covenant that God made with the the ancient Israelites and them only (not the Assyrians, Egyptians or Phoenicians), and they voluntarily agreed to it (Ex 19:3-8). However after about 1000 years, they had violated the terms of the covenant so much, God considered it broken by them (Jer 31:31-32).
If a Christian attempts to be righteous in God's eyes via the OT (i.e. be justified by the old Jewish law), he'll go to hell (Gal 5:4).
As scripture, the OT still has usefulness (2Tim 3:16-17), but not as a source of commands.
The "violent" parts of the OT were because it was also the basis for law in the theocracy of Israel, and thus included crimes and punishments. Our laws today also have "violent" parts such as capital punishment.