Is the lesson for native-chinese-speakers about speaking English? If so, interesting, I haven't actually seen this (presumably common?) oopsie before. It also hadn't occurred to me how crushing of an insult it is, but damn yeah it sure is.
A "thing" or "stuff" in Chinese is 东西 (dōngxi). That's literally "east-west" if you pick the individual characters apart. That's what the footnote refers to.
Calling somebody 不是个东西 (bùshì ge dōngxī) means something along the lines of being good for nothing, i.e. an insult. Translating it literally, it would be calling somebody "not a thing".
Only if the employee decides they were harassed. This was a "loophole" in a harassment training package a former employer used. Basically if you were of an ilk that will always be believed by HR you get a blank check on what to consider harassment. A classic some are more equal than others scenario.
Seems like you can read this 2 ways, the additional way being allowing workplace relationships that have a touching component to it. Regardless of how appropriate that is at work.
"Why didn't you tell us you hired something new?"
"They work here for 2 weeks now"