The presence of a sunburn is orthogonal to the fact that you do, in fact, become exposed to radiation in sunlight. That is unequivocally true and trivially proven, whether you receive a sunburn or not.
I don't think the person you are replying to meant that sunlight exposure unconditionally causes cancer, and was simply addressing radiation scare and putting it in context.
All the downvotes notwithstanding, there is a direct correlation between the number of severe burns you've had and your chances of getting skin cancer[0], unless you have a genetic predisposition to skin cancer.
A moderate amount of sunlight on skin, without burning, is actually healthy for you, unless you 1) have various illnesses (lupus, for one), or 2) are genetically predisposed to skin cancer.
The say all we have to worry from the sun is skin cancer. That Solar flares don't cause other cancers. Remember this is the same science community and government that recommended margarine was safer than butter. That salt was dangerous and to be avoided which isn't believe to be be 100% accurate. They also created a food pyramid. We were told to eat lots of breads and pasta and fruit which contains sugars. People drank lots of juice. We were told to avoid foods with fat. Diabetes greatly increased ever since and now we are hearing it's the carbs and sugars that are more of a concern than fat.
We are told that mostly UV and electromagnetic radiation reach the earth and Sunlight is danger of skin cancer. Have we all read the peer reviewed studies and do we really know how often the sun potential sends a surge of Gamma radiation through your body? Isn't a great concern of long term solar system exploration about astronauts getting all sorts of cancer? How sure are we that the earth's atmosphere is protecting us from the same gamma radiation and that it isn't causing more than just skin cancer? Science evolves and surprises often occur. I personally am not so convinced that the Sun couldn't cause much more dangerous types of radiation myself but, I admit this isn't an area of research for me.
