The more people hear the Gospel, it stands to reason that more will accept it and devote themselves to God. It would only be grossly unfair if God demanded that only those who heard can be saved, but since He does not, it is a non-issue, and your concerns are null and void. Preaching the gospel leads to some people getting saved who wouldn't have been if they hadn't heard. That is ridiculous, even if there are millions of other factors affecting salvation. Perhaps that is your confusion, so that you think you see contradictions, where there are none.
All human beings have an equal chance of salvation.
They will be judged on their circumstances and what they have done with their moral and theological knowledge, whatever that may be. We believe that He arranges circumstances so that everyone has multiple chances to believe in God, become a Christian, etc., by the power of His Providence, yet not violating human free will in the process.