Full-fledged biopsies, without any other indication, are exaggerated. A simple colonoscopy isn't. Nor are the other, standard, screening tests. And still most people just don't even use the standard screening options. My personal guess, because people are afraid the screening is finding something. Without the screening, you can happily continue your life in ignorance. Usually, this is regretted if they actually have cancer later, once the cancer is so advanced that actual symptoms manifest.