Why did Dutch leaders fear Cromwell?

Did the Dutch hate Oliver Cromwell?

They were more frightened than hateful, especially by his military rise and role in executing a king.

Dutch attitudes toward Oliver Cromwell are described as fear rather than simple hostility. To aristocratic and republican leaders alike, Cromwell seemed to have risen from an ordinary social position to supreme power through military command. His role in the regicide made him still more alarming because the Dutch political order had exploited a dynastic vacancy without executing its own Orange ruler. That reputation helps explain why a confederation with the Commonwealth looked less like partnership and more like exposure to a formidable soldier-politician.