Most doctors care, but they're all human. Every doctor will have slightly different experiences and world views under their belts that affect their opinions and treatment styles. Whatever doctor was in charge of your case might have felt a colonoscopy was an unwarranted invasive procedure at that stage of your treatment. You can always request procedures or ask about alternative treatment options from your end. You can also find a different gastrointestinal group to move forward with. It's your health after all.
The exact risk factors that indicate a possibility of Crohn's disease are not very clear, so it's not always easy even for the professionals to put a finger on a definite risk factor. You can always talk to your doctor about the necessity of a colonoscopy in this case to understand the condition better.
Most doctors will take into account your symptoms, age, family history and rule out other illnesses. If they suspect Crohns, they'll start with labs and the less invasive CT scan of Abdomen with contrast which will show a "likelihood of inflammatory bowel disease (IBD)" if Crohns or UC is present. The Dr will likely then order a colonoscopy for a definitive diagnosis. This will show if IBD is present, the portion of colon affected and best course of treatment.