There are many very nutritious vegetables that cannot be consumed without cooking them.
Grilling meat on the barbecue was once thought to be very carcinogenic. Then they found out that when the drippings fell into the flame, they created a new anti-carcinogenic substance. Too much coffee is bad for your digestive system, but they found that the process of making espresso actually creates a substance that fights colon cancer.
Rhubarb is toxic if I eat too much of it, but in moderation is antiparisitic. Same with garlic, too much is toxic but in moderation is antiviral, antibacterial, antifungal. The toxicity of any food comes from overconsumption, no matter how healthy or unhealthy it is deemed.