It depends. If nobody is harmed by laughing about that topic (for example, senseless OC joking regarding to this topic when no real person is hurt) it's okay. A little tasteless somtimes, but okay.
It's only serious if you laugh about victims, or in front of people who can't take the topic with humour. Empathy and brainscore are the key to laugh about even serious stuff and still not offend anyone with it :3