Either the painting is ugly or beautiful, one of the conclusion is wrong. That's obviously a nonsense.
It doesn't work that way, the same reason why both conclusions the painting is ugly and beautiful are valid, is the reason both conclusions God is real, and God is not real are valid.
Beauty and ugly applies to agency of a decision, love and hate. Agency is what makes a decision turn out the way it does. That either conclusion beauty and ugly can be reached, means that if beautiful is chosen that it is equally valid that the love for the painting is real, as it is to say it is not real. If the existence of the love is fact, then this factual love would force the conclusion beautiful, and the conclusion ugly could not be reached.
And we can see that the term God is also defined in terms of agency. Some of the most well known titles for God, God the creator, and God the holy spirit, refer to agency. You can see that the term spirit refers to agency, because spirit is also defined in human free will as what does the job of choosing.
You simply have no idea at all where exactly the line is between fact and opinion. That line is at a decision. It is a fact that a decision is made, what the options are, what the result of it is, but it is opinion what it is that makes the decision turn out the way it does.
This is also why freedom of religion is in the laws. If it were a matter of fact issue, then in principle the fact would simply be enforced by the government, like all other facts. In the case of communism, scientific socialism, the fact is then that God does not exist, hence religion is outlawed, and in the case of a theocracy, the fact is then that God exists, therefore people are forced to accept God exists.