Calvinism turns words topsy-turvy. According to Calvinism, you can tell the truth and it would still be a sin, because your motive is wrong. If this were so, all of God's commands would be meaningless. If it is a sin for an unregenerate man to tell the truth, then why command him against lying? If everything the unregenerate man does is sin, why would laws or commandments be necessary at all?
Jesus himself said sinners can do good.
Mat 7:9 Or what man is there of you, whom if his son ask bread, will he give him a stone?
10 Or if he ask a fish, will he give him a serpent?
11 If ye then, being evil, know how to give good gifts unto your children, how much more shall your Father which is in heaven give good things to them that ask him?
12 Therefore all things whatsoever ye would that men should do to you, do ye even so to them: for this is the law and the prophets.
Jesus did not say sinners are unable to do good, he said they "know how" to give good gifts to their children. Verse 9 shows the motive, it is understood the son is hungry, therefore the man is giving him bread to nourish him. Every decent parent would give food to their children and oftentimes strangers if they were hungry.
To say something is evil because there is self-interest involved is a fallacy. Even Christians desire God to be pleased with them, this is self interest, it is selfish. It is not wrong to want God to be pleased with you, and we are told to work to earn rewards. Is that not selfish?
It is when something is purely selfish it is wrong. If you give food to strangers only so you can tell yourself you are a good person, this would be wrong. But if you gave food to a stranger because you were sincerely concerned for their health, this is not wrong whatsoever.
Luk 6:32 For if ye love them which love you, what thank have ye? for sinners also love those that love them.
33 And if ye do good to them which do good to you, what thank have ye? for sinners also do even the same.
34 And if ye lend to them of whom ye hope to receive, what thank have ye? for sinners also lend to sinners, to receive as much again.
35 But love ye your enemies, and do good, and lend, hoping for nothing again; and your reward shall be great, and ye shall be the children of the Highest: for he is kind unto the unthankful and to the evil.
Jesus is not saying everything sinners do is evil, he is simply saying it is not that which would merit reward. Everyone loves persons who love them, everyone does good to those that do good to them. It is not evil, but it is nothing very special either.
But note in verse 35 when Jesus says it is far better to love and give to those who hate you, he promises a reward. This is self-interest, it is a selfish motive to a degree.
But again, Jesus is not saying the unregenerate cannot do good. When you tell the truth, that is good, it is not evil. Lying is evil. If a mother feeds her child, that is good, it is not evil.
And we see unregenerate men doing very unselfish deeds. A person rushes into a burning house to rescue a child heard screaming, a soldier leaps on a hand grenade to save his friends in the foxhole. Regardless of motive, these are good deeds.
When the scriptures say there is none good, no, not one, it is speaking of being 100% good, without any sin whatsoever. There is only one person who did this, Jesus Christ. The rest of us have "come short"
Rom 3:23 For all have sinned, and come short of the glory of God;
This verse is not saying man cannot do good, it is saying all men have sinned and come short of the glory of God. To attain the glory of God you would have to be perfectly sinless, which no man but Jesus has or will ever do. But it is not saying we cannot do good. It is like shooting an arrow at a target. Your arrow flies a distance, but it falls short of the target. That does not mean your arrow did not leave your bow.
Eze 18:24 But when the righteous turneth away from his righteousness, and committeth iniquity, and doeth according to all the abominations that the wicked man doeth, shall he live? All his righteousness that he hath done shall not be mentioned: in his trespass that he hath trespassed, and in his sin that he hath sinned, in them shall he die.
This verse is speaking of a lost person who "in his sin" that he hath sinned, "in them" he shall die. So this is a lost person. But God himself says this man has "done" righteousness. Man can do true good that is recognized by God. But if you sin even one time in all of your life, then you have come short of the glory of God. The wages of sin is death, and you must pay that penalty.