Is too much sugar directly responsible for diabetes type 2?

Not directly: High sugar is by definition diabetes so high sugar level (if meet criteria) will directly give you the diagnosis of diabetes but eating/consuming sugar will not cause diabetes in the short term. Overtime, eating a lot of sugar will cause obesity, Insulin resistance which will lead to type 2 diabetes.

No: In the child diabetic, the general problem is that the pancreas quits producing Insulin so your body can not utilize the available sugar. In the adult diabetic, your cells become resistant to the available insulin. The result is too much sugar in the blood. If you are a diabetic and you eat a lot of sugar, then this can make your diabetes worse, but it is not the cause of diabetes.