The context for the latter remark was the case of female adultery. Under Jewish law, the female offender would be stoned to death, while the male offender suffered no consequences. Jesus' remark was in allusion to this gross inconsistency. So the context of the quote does not fit your situation; the jurors were not themselves guilty of murder nor in the position of condoning murder in discriminatory fashion.
On balance it would seem that Christian theology is more inclined against capital punishment than for, so your ire is properly directed against the Stalinization of the Gospel, or maybe the Reformation, rather than its original incarnation.
MBS
"For if you love those who love you, what reward have you? Do not even the tax collectors do the same? And if you salute only your brethren, what more are you doing than others? Do not even the Gentiles do the same? You, therefore, must be perfect, as your heavenly Father is perfect."
-- Matthew, 4:43;48