I don't really care when people joke about murder. As far as I'm concerned, anyone who destroys the environment deserves to be destroyed themselves. I'm not even joking about this... I despise those who seek to destroy the environment and use it purely to make money.
TBH there's alot of topics whether traditionally insensitive or not that can be used as an inappropriate joke. I think it depends on how the topic is discussed virtually. I mean I dislike alot of forms of racism but I laugh at some jokes like that. Same thing is sexism and other things. I mean for an example I'd laugh at a sexist joke pointed at guys if it was funny and not inappropriate. Rape is arguable. But generally should not be discussed lightly. So I see this topic as a bit of a gray area to be frank.
And just to many stuff to list....Yeah its a joke but did you know THAT JOKES HURT?! Yeah! It might just be "Oh i'm not acutally saying it im just joking!" Well.....Jokes can be very offensive~!
Anything involving rape, abuse, suicide, self harm, illnesses, disabilities, or any major events or people who have caused a great deal of harm or death (like wars, mass executions, etc.).