Let me add my understanding ....
God has place within all of us a moral standard. Meaning simply this, regarding whether they have heard or had available to them the Gospel message, innate within mankind is a moral standard, and it is that standard that all civilizations and cultures establish some kind of moral law by wich they live amongst each other.
Probably the best Scripture to apply to this is found in Romans 2:12-16 (TLB) which says, "He will punish sin wherever it is found. He will punish the heathen when they sin, even though they never had God’s written laws, for down in their hearts they know right from wrong (the innate moral standard). God’s laws are written within them; their own conscience accuses them, or sometimes excuses them. And God will punish the Jews for sinning because they have his written laws but don’t obey them. They know what is right but don’t do it. After all, salvation is not given to those who know what to do, unless they do it. The day will surely come when at God’s command Jesus Christ will judge the secret lives of everyone, their inmost thoughts and motives; this is all part of God’s great plan, which I proclaim."
Someone once said the Book of Romans is 16 chapters of pure doctrine for the church! It is the standard for which most churches and denominations build their creeds around!
I think Paul answers you question without challenge, and I know that whenever this question is asked of me by, let's say an atheist or agnostic kind of person, this is my boilerplate answer!
You're forcing a 'moral standard' that you're imagining into the text, which seems to be the normal thing to do with you gospel regeneration types. It is 'THE LAW' that is being referred to in Ro 2, not an innate 'moral standard' that's going to either send one to hell or to heaven in the event of the absence of the gospel:
12 For as many as have sinned without law shall also perish without
the law: and as many as have sinned under
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 Gentiles that have not
the law do by nature the things of
the law, these, not having
the law, are
the law unto themselves;
15 in that they show the work of
the law written in their hearts, their conscience bearing witness therewith, and their thoughts one with another accusing or else excusing them);
16 in the day when God shall judge the secrets of men, according to my gospel, by Jesus Christ.
17 But if thou bearest the name of a Jew, and restest upon
the law, and gloriest in God,
18 and knowest his will, and approvest the things that are excellent, being instructed out of
the law,
19 and art confident that thou thyself art a guide of the blind, a light of them that are in darkness,
20 a corrector of the foolish, a teacher of babes, having in
the law the form of knowledge and of the truth;
21 thou therefore that teachest another, teachest thou not thyself? thou that preachest a man should not steal, dost thou steal?
22 thou that sayest a man should not commit adultery, dost thou commit adultery? thou that abhorrest idols, dost thou rob temples?
23 thou who gloriest in
the law, through thy transgression of
the law dishonorest thou God?
24 For the name of God is blasphemed among the Gentiles because of you, even as it is written.
25 For circumcision indeed profiteth, if thou be a doer of
the law: but if thou be a transgressor of
the law, thy circumcision is become uncircumcision.
26 If therefore the uncircumcision keep the ordinances of
the law, shall not his uncircumcision be reckoned for circumcision?
27 and shall not the uncircumcision which is by nature, if it fulfil
the law, judge thee, who with the letter and circumcision art a transgressor of
the law?