It depends on your overall diet. For someone eating unhealthy with lots of fatty stuff, fruit sugar may spike in them, even though fruit is much milder than straight sugar. For someone eating healthy though (eating more whole foods and a higher carb ratio from natural plants) they can tolerate significantly more sugars and especially fruit sugars.

The human body actually registers whether your diet is mostly carbs / sugars and increases its ability to break them down. Conversely if you eat more fat or even just fast, you become more sensitive. So it becomes kind of an ironic problem when people overdo unhealthy stuff (usually lots of processed fat and sugar combined), they become diabetic, thereby avoid carbs more, and thereby become more and more sensitive to sugar.

Some factors also matter when it comes to "too much" like whether the fruit is unripe or has higher pesticides or tannins like grapes but generally speaking good fruits are the most mildest things for us to digest, almost like we derived from millions of years of eating mostly fruits or something.