What does it mean when a doctor says a certain xyz condition won't increase my risk of cancer above the "baseline risk" of the general population. what is baseline risk?

If you take the frequency of condition x in the population with no known risk factors that is one definition of the baseline risk. To say it another way, it happens occasionally and that is how often it does at random. To consider some agent y as increasing cancer risk, you must show more than the expected baseline number have cancer if it is used.

That refers to the risk of an individual without the xyz condition as the baseline risk in the general population meaning that condition xyz does not increase the risk of cancer above the risk for the general population.

Agree with Dr. Ferguson. You can reduce your risk of cancer by adopting healthy habits: Eat a mostly vegetarian diet, avoid alcohol, tobacco and street drugs, avoid excessive exposure to sun, get HPV vaccine, exercise 30 minutes each day, drink enough water so your urine is mostly colorless.