Do you realize how shockingly violent the cross, the symbol of the Christian faith, is?
A cross sits there and does nothing. I suppose if you picked up that cross and beat someone over the head with it then that act would be violent, carried out by a violent person, but the cross itself would have done nothing of its own accord. If you are referring to the manner in which the romans (and the persians before them) executed criminals, yes that method appears to have been tortuous, violent, humiliating, and excruciatingly slow. Still, in no instance did the cross perform the violence. The people did. As far as the cross, the instrument by which death was inflicted on Jesus and the robbers, becoming such a lasting symbol, something backfired. Jesus was tried, convicted, and extremely humiliated to his death in an effort to eliminate him as a potential troublemaker, and to send a message to his followers that he was powerless and insignificant. Among his followers that got turned around and spun into a story of his self-sacrifice and divine sacrifice for the ultimate salvation