cartoons about serial killers

How do you decide when a cartoon or joke is harmless, or when it hurts people? Of course, the same cartoon can amuse one person, offend another person and confuse yet another. But overall, are there principles or ways of determining where a cartoon stands?

Take this cartoon from Matta as an example:

Should a serial killer be offended by this? Does it make fun of him or her? Or it is simply a funny idea which happens to be about serial killers and their weapons? After all, it's not like one of those jokes that starts with a line like "Serial killers are so disgusting that ...."


I'm asking these questions because seeing this cartoon inspired some "Homophobe Advice" cartoons, and I'm wondering whether people will find them offensive and why....

Here's an example:

Is this offensive? Why or why not? If you do not find it offensive, why might others find it offensive? Or if you do find it offensive, do you think that it is universally offensive?

Would love to hear your thoughts!