I wouldn't say 'out of contol'....quite calm and sensible, really....as discussions should be....
People have all sorts of ways to deal with crises/grief/etc ....one of which is to make [what appears to many] odd choices for humour.
The 'unfortunate' part is that not everyone will share/appreciate the 'mirth' .... at which stage it's more appropriate to simply move on....and leave the 'jokes' for like-minded people.
Open forums such as this one attract such a diverse group you can be certain to upset someone, sometime with 'missplaced' joking...