Somehow these guys seem to be unable to say that Christ died for their sins.
There is a difference between dying for somone's sins willingly and being killed for someone's sins. Besides, it's not biblical.
[E]veryone shall be put to death for his own sin. [Det 24:16, 2 King 14:16].
The person who sins will die. The son will not bear the punishment for the father's iniquity, nor will the father bear the punishment for the son's iniquity; the righteousness of the righteous will be upon himself, and the wickedness of the wicked will be upon himself. [Eze 18:20]
Are you saying that Christ sinned?
As you know, but for the benefit of lurkers, they cannot say that honestly, for in the Apostolic theology Christ did NOT die for anyone's sins. For them, Christ's suffering and death, and resurrection, was only good to give man the possibility to decide for himself if he wanted to be saved. So in their theology, Christ finished nothing, He just handed the ball off to man and waited to see who gained enough yards to be saved.