The issue is not fallen mankind, since all Christians know that Adam brought sin and death upon the human race, and that all have sinned and come short of the glory of God.
The issue is the distortion of human beings through what is called "Total Depravity", which even denies that the unsaved have consciences and often follow their conscience. Notice "
being altogether averse from that good".
"III. Man, by his fall into a state of sin, hath wholly lost all ability of will to any spiritual good accompanying salvation:so as, a natural man, being altogether averse from that good,and dead in sin, is not able, by his own strength, to convert himself, or to prepare himself thereunto."
Westminster Confession of Faith
But Scripture does not teach this:
ROMANS 2
12 For as many as have sinned without law shall also perish without law: and as many as have sinned in the law shall be judged by the law;
13 (For not the hearers of the law are just before God, but the doers of the law shall be justified.
14 For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves:
15 Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another)
16 In the day when God shall judge the secrets of men by Jesus Christ according to my gospel.
Also, the power of the Gospel and the power of the Holy Spirit are denied in bringing men to salvation. Instead Five Point Calvinism teaches that sinners are regenerated
BEFORE they have believed the Gospel. That is patently false.