2. If it was false, then God did not know; because knowledge is only knowledge if it is true; false knowledge is ignorance or deception.
3. If God's knowledge was true, then it's opposite (that He would not create man) was false.
4. In other words, God's knowledge of man's creation and the fact of man's creation are definite and coterminous.
5. In other words, the statement God knew He would not create man is false.
6. Consequently, it was true that God would create man, and it's opposite was false.
7. Therefore, the question "If God knew that man would sin, why create man?" is self-contradictory.
If God Knew That Man Would Sin, Why Create Man? Part-1
Arithmetic of Foreknowledge
Aristotle’s Temporal Logic and the Problem of Foreknowledge in Jesus’ Prediction of Peter’s Denial
Aristotelian Determinism: A Solution
Does God Know the Future? Epistemic Concerns and Rational Fideism
Reliability, Predictability, and Paul the Octopus