Now, it is obvious to anyone that the Buckwheat Groats are a comedy group. Their other songs are equally ridiculous. At the same time, "Can't you take a joke," is a pretty lousy comeback to someone who is genuinely hurt or offended.
We shouldn't stifle creativity just because it could offend people, but we should tell people not to be upset by something that may remind them of their own very painful experiences. It's easy to think that humour is just humour when you find it funny and easy to think it is offensive when you don't.
Progress requires both those are transgressive - to find our faults and find new ideas - and those who are reactionary - to push back against new ideas and thus raise the hurdle they have to get over to be implemented. That these two forces butt against each other and cause each other emotional pain is a sad consequence of the only way that things can be.
It isn't the comedian who is bad or the person who is offended by the comedian. It is that the world is drenched in pain and getting better is the most painful thing of all.