You obviously have very little knowledge of the topic you're presenting yourself as an expert on.

If I thought I were an expert, I would be answering questions instead of asking questions.

What are the arguments that a human can outplay a computer at poker?

The fact that you don't see computers beating the best humans (except in some somewhat marginal forms of poker, and even there it's debatable), and in most forms of poker, not even the semi-good players.

That isn't an argument unless the best humans frequently play against computers. Do they?

A human could be better than a computer at beating another human. In a game with one computer and four humans, I can easily believe that one human might win more than the computer did.

In a game with four well-programmed computers and one human, I predict the computers will trounce the human regularly. I'm not an expert at poker; but I am an expert at computation, so I feel pretty confident about this prediction.

(A game with 3 well-programmed computers, one human, and one poorly-programmed computer would count as a game with 3 computers and 2 humans.)