But the Communists were sufficiently content with their own analysis of the course of history behind them to be satisfied with the chart of direction which they had chosen for the voyage ahead.

请问专家老师们红线部分to be satisfied with the chart of direction which they had chosen for the voyage ahead.应该是和sufficiently content with their own analysis of the course of history behind them并列的结构，那么为什么不在to be之前加上逗号进行分隔呢，原文这样虽然能读懂但是否会容易引起误解。