(1) "Good and evil" is nonsense.
There really is no good and evil. Disease, death, natural disasters and all the suffering that results from it is only arbitrarily defined as 'evil' by ourselves, there is no 'evil' inherent in the physical laws of geology that result in earthquakes, and no 'evil' in the facts of chemistry that accidentally cause cancers. They are naturally occurin parts of physical reality, and proceed completely without moral considerations. We only call
things "evil" or "good" out of convention.
The following is quoted from my "Opposites are Illusions" by Vexen Crabtree
"What is good for one being is frequently bad for another. For example in nature the whole cycle of biological life is based on death and recycling. [...]. All predators find it good that prey is available; if you protect the prey you harm the predators, and whilst it is bad from the prey's point of view to be eaten, it is necessary from the predators point of view. In nature, natural survival is violent and competitive.
Bacteria1 feed on biological chemicals to survive and breed. What is good for them is bad for us. While antibiotics are good for us and reduce our suffering, their usage create suffering and death for countless other minor species. What is good for one species is bad for others. While one culture may consider multiple marriage to be a virtue of love and positivity, another considers it an evil sin. What is good in one culture is bad in another. What was good in the Old Testament of the Christian Bible is bad in the New, what is good in the Buddhist Pali scriptures is wrong in the Therevada, what is considered an ethic by one group in society is considered wrong in another. What the homeless rightly do to survive is a "social evil" to those with homes, and how governments collect tax is evil to the poor person but a social necessity. Good and Evil are impossibly complex, inherently subjectivist. There are no actions that are good for everyone, and there are no actions that are bad for all species."
You explicitly depend on "a priori intuition", but, what you consider 'intuition' is just simplification and illusion. That is no basis for the grand conclusions that you make.
(2) Even if good and evil existed, it wouldn't imply the existence of a good god.
Lots of opposites can exist without the requirement for a God to have created them on purpose. And, with the cause of good and evil, it is as logical to assume that a good god created them as to assume an evil god did ("Evidence that if there is a God, it is an Evil One" by Vexen Crabtree (2003))
The failings of your argument:
(F1) It is no good relying on 'instincts' as evidence to turn a subjective opinion into an objective dualism.
(F2) It is no good to claim that a good god is the only valid cause of the dualism of F1, without proving first that god exists, and that good and evil have a basis in fact external to the human mind (F1).
So, your requirements to backup your arguments are:
R1: You need evidence that good and evil are absolute and objective. Try citing some examples - I bet every one you can think of it subjective. You only need to come up with one
example to win this argument in principal, so I'm sure you'll consider this easy.
R2: Prove that good and evil require the existence of god (that it is therefore distinct from other opposites that exist (apparently) without the need for god.
R3: Prove that God (the explanation for R2 and R1) itself exists. It is no good saying that F2 implies this, when F2 itself remains unproven (it is a therefore circular argument, with no proof for either part).