The Bible is written in parable form (Psalm 78:1-2, Mark 4:34) and if you read the scripture in question in Romans 5 as a surface text you will get confused, in my opinion. In English, the term 'all' or 'all men' would simply mean everyone or every man. However, we have to compare the Bible with other parts of the Bible to get at the Bible meaning of the term, which appears to me to be a parable term used to describe 'all those who are saved'. That is a different meaning from just the normal English interpretation of the term 'all'. Someone here named Crossnote quoted a very good scripture to help clarify, in my opinion, how God uses the term: "Even the righteousness of God which is by faith of Jesus Christ unto all and upon all them that believe: for there is no difference:" This is showing that the term 'all' in the Bible can be used to describe a specific group of persons unto whom and upon whom this salvation of righteousness by faith occurs. It is saying: All = All who believe. It does not seem to be saying All persons who are on the planet or who were or will be; only those who believe. However, other verses in the Bible address whatever predestination questions people seem concerned about. My opinion is that the Bible says that God enables those who he wants to be his true believers (his sheep so to speak) to hear his voice and to believe on him. It is an act of God. Without God first enabling a person to believe, they would not be able to believe.
People might find it hard to imagine that God would use the term 'all' to mean only 'all who believe' and not to just mean all persons generally. However, the Bible is full of these sorts of usages where a term needs to be defined by the Bible itself, not by modern English. For example, consider the term 'blessed'. A person uses this term today to mean something good has happened to them and they were lucky it did or they were enabled in that thing because God was good to them. For example, I was blessed to get a good grade in school, or I was blessed to make a lot of money. However, the Bible term blessed has a somewhat different definition. It is used to describe those persons who are saved. For example: "Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered". When the Bible says, "And the scripture, foreseeing that God would justify the heathen through faith, preached before the gospel unto Abraham, saying, In thee shall all nations be blessed" Here, we can see (if God has enabled us to see) that the term "all nations" is not referring to everyone on planet earth (like every Phoenician, or every Russian, or every American). Rather, the term "all nations" must mean all those who are saved. We know this because these are the people who are described using the term "blessed". Blessed means those whose sins are covered.
I would say that if it includes 'all who believe, then that means 'all who believe. But to the verses in question .
14Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam's transgression, who is the figure of him that was to come.
15But not as the offence, so also
is the FREE GIFT . For if through the offence of one many be dead, much more the grace of God, and the GIFT by grace,
which is by one man, Jesus Christ, hath abounded unto many.
THE GIFT HAS TO BE RECEIVED.
16And not as
it was by one that sinned,
so is the gift: for the judgment
was by one to condemnation, but the FREE GIFT ( GIFT HAS TO BE RECIEVED)
is of many offences unto justification.
17For if by one man's offence death reigned by one; much more they which RECIEVE abundance of grace and of the gift of righteousness shall reign in life by one, Jesus Christ.) ( ITS BEEN RECIEVED HERE )
18¶Therefore as by the offence of one
judgment came upon all men to condemnation; ( ALL MEANS ALL HERE) even so by the righteousness of one
the FREE GIFT came upon all men unto justification of life. ( SAME HERE ) IT COMES UPON ALL IN THE SENSE OF BEING AVAILABLE TO ALL , BUT THEY NEED TO RECEIVE
19For as by one man's disobedience MANY were made sinners, ( CLEARLY HERE THIS MEANS ALL WITHOUT DISTINCTION ) so by the obedience of one shall MANY be made righteous. ( IF THEY RECIEVE )
20¶Moreover the law entered, that the offence might abound. But where sin abounded, grace did much more abound:
21That as sin hath reigned unto death, even so MIGHT !!!!! grace reign through righteousness unto eternal life by Jesus Christ our Lord.