The great weakness of people who tell us evolution is “only a theory” is that they offer no alternative explanation for how we breed animals, how viruses can adapt and change, etc. As one of my students exclaimed after getting frustrated watching a video on the evolution of language, “Let’s just say god did it and forget the whole thing.”
Forget the whole thing is exactly what anti-evolutionists want to do. They don’t want their lives cluttered with trying to understand the world around us. In short, they offer nothing.