The fact that evolution is less than a certainty is not an argument, it is an observation, a fact, a truth claim, a certainty. Evolutionists who refuse to admit as much have relegated themselves into the realm of non-reason. They sound like Bill Clinton trying to explain the meaning of "is."
The fact that evolution is uncertain does not render it useless or unscientific. All scientific theories are uncertain. Does that mean we should stop teaching science? Evolution has a similar status, as far as degree of certainty goes, as does quantum theory, relativity theory, and many other scientific theories. We cannot observe atoms or space-time curvature either. These are the best theories we have for the observations. Similarly evolution is the best scientific theory for the observations. Furthermore, and I'm not necessarily pointing to you in particular, many creationists focus more on disproving evolution than they do supporting their own ideas. Even if evolution were to be completely debunked, it would not necessarily render creationism true. (or ID or any other idea, for that matter). Any alternative to evolution should rise or fall on its own merits.