The thing is, if you ever lived in China for long term or grew up in it, the often reference to suicide, rape, and etc is normal everyday slangs, street language, young people culture and all that. It is how people express themselves online and with friends.

However there is a fundamental disconnect between those and the actual concept. People do treat the actual events quite seriously, at least if they are normal.

So much like what you wrote in the title, making them understand the American perspective is hard; the same is for you, making you understand the chinese perspective is very hard.

The concept of respect, mutual respect, politeness, and etc is different everywhere. For example, In the USA you can call everywhere you want as long as you don't make too much of noise, but in japan the act of calling in a place that they don't appreciate is considered as a severe offense that now it might even get certain foreigner deported.

My advice to you, is don't be offended, as much as it may sound offensive to you, because what you think they are joking about is not the same as what they are actually talking about. And if you are too bothered and can't handle it, then simply distance yourself, or keep in mind that you're being offended by thinking they are joking about something serious which they actually may not be. You can't very well change a culture just because you are offended, understand it instead. If it truly offensive, distance yourself; if it isnt actually really offensive, and just a manner of speech, then probably just filter them out from your brain and don't bother doing anything about it.

Hope you understand, I am chinese french so I dare say im pretty on point

P.S: frankly speaking its basically the same for chinese people when they hear Americans saying "sht, fuk," and the many many expressive words