表达 “make a joke of something” 的意思是 “取笑、嘲笑或幽默地谈论一个本该严肃对待的事情”，也就是我们常说的 “对…付之一笑”。

You shouldn’t make a joke of people’s hardships.
你不应该拿别人的困难开玩笑。

They made a joke about their boss’ ability, but it was true that he was unable to lead and motivate the staff.
他们笑话老板的工作能力，不过他确实不会领导和激励员工。

She’s making a joke about her exam results but seriously, it might affect her chances of getting a good job.
她对自己的考试成绩付之一笑，但说真的，这可能会影响她找到好工作的机会。