The problem is that it's always depending on the dose.

Fictional example: You can show an increased cancer risk in animal testing if amount x is consumed regularly. But then X is also the equivalent to 20% your body weight in sugar per day.

So now you don't just suspect it's carcinogenic, you know. But it's still completely irrelevant when used as an ingredient in food obviously.

That's basically like saying we need more studies on the toxicity of water as we know it is indeed toxic if you consume too much.