Some arguments use human conduct as a benchmark: if a person withholding a benefit would be called miserly or unjust, the same label must apply to Allah. This resembles a form of analogical reasoning from the seen to the unseen.
Human giving and withholding, however, occur amid limited resources, property rights, promises, obligations, and dependence on other creatures. Transferring all these conditions unchanged to Allah is an unsound analogy.
Human examples may clarify a concept, but moving every condition to the Creator disregards an important difference in the cases.