How can one who is a slave to sin and death, ruled by the nature of sin and death, choose other than what is ultimately sinful and leads to death?
Not much freedom of choice in that condition.
Freedom means the ability to do what you want to do.
Sinners want to sin. That is ALL sinners want to do. That's why we call them sinners.
Sinners are absolutely free to do what they want to do- sin.
And everything a sinners does is sin.
The Bible says, "The PLOWING of the wicked is sin."
The Bible says, "Their RIGHTEOUSNESSES are as filthy rags."
Everything the sinner does whether he volunteers for boyscouts or helps an old lady across the street- EVERYTHING he does is sin.
Whatsoever is not of faith is sin- that's what the Bible says.
Everything not done for God's glory is sin.
Sinners do not do things for God's glory. They do things for their own purposes- even if it is seemingly good things.
Motive is everything.
Sinners are free to do what they want to do- sin.