organized religion were unknown to them of course... but they felt the presence of God and they knew it. Thats why they practiced those kind of worship but in corruptible manner... it was in the Bible.
Christians are misled, and some are evil. It's in the Qur'an, so it must be true.
"If only they [i.e. Christians] had stood fast by the Law, the Gospel, and all the revelation that was sent to them from their Lord, they would have enjoyed happiness from every side. There is from among them a party on the right course, but many of them follow a course that is evil" (5:66).
"Oh People of the Book! Commit no excesses in your religion, nor say of God anything but the truth. Christ Jesus, the son of Mary, was (no more than) a messenger of God, and His Word which He bestowed on Mary, and a spirit proceeding from Him. So believe in God and His messengers. Say not, 'Trinity.' Desist! It will be better for you, for God is One God, Glory be to Him! (Far exalted is He) above having a son. To Him belong all things in the heavens and on earth. And enough is God as a Disposer of affairs" (4:171).
for what i know, atheist themselves argued for what really atheist means...
From what I know, Christians themselves have argued (since the after apostles) and are still arguing about what Christianity really means; e.g. the doctrine of the Trinity and the divinity of Christ only became canonical with the Nicean Council, a full 300 years after Christ; Christians today still debate over
conditional vs
unconditional election,
limited vs
unlimited atonement, etc.
regarding the mind state of a new born child or his/her capability of belief... how do you know that a newborn child have no knowledge of God?
if a newborn child have no knowledge of God at all does it mean that God does not exist? kung walang alam ang newborn child about parents does it mean na wala siyang mga magulang? if a newborn child has no knowledge of moons and stars does it mean that there are no moons and stars?
Regarding the state of mind of a newborn child, how do you know that a child has no knowledge of unicorns?
If a child has knowledge of unicorns, does that mean that unicorns exist?
Saan ba talaga nakatayo ang mga atheist? sa paniniwala na since ang bata ay isinilang na walang knowledge of God ay puwede na nilang sabihin na walang Diyos?
Saan ba talaga nakatayo ang mga Kristiyano? Sa paniniwala na dahil ang bata ay natatakot sa multo na ibig sabihin ay may multo?
Creation itself shows that God exist.
Geology, minerology show that the Earth is round and it's older than 6,000 years. Evolution shows that humans likely evolved from basic life forms into progressively more complex and intelligent species.
Prove the non-existence of God sa kahit anong paraan? Is there any intelligently, specifically and truthfully proof the God does not exist?
You can't 'prove' a negative. The burden of proof is with those that posit the positive. You can't prove the Flying Spaghetti Monster doesn't exist.
Thinking that God does not exist is not a proof for the non-existence of God.
Believing that God exists is not proof for the existence of God.