God knew men would have so many excuses so he made sure:
Roman 1:20-21
them, because God has made it plain to them. For since the creation of the world God’s invisible qualities, His eternal power and divine nature, have been clearly seen, being understood from His workmanship, so that men are without excuse. 21For although they knew God, they neither glorified Him as God nor gave thanks to Him, but they became futile in their thinking and darkened in their foolish hearts.…