When John Cleese stopped in Singapore on his Divorce Tour, he talked about Black Humour. Black Humour typically covers topics like death, religion, sex, cartoon/extreme violence.
An example of black humour from Jim Dale:
"What is black and white and crawls along the ground?"
"A wounded nun"
In the next weeks, Cleese thought of that 13 times after hearing that when walking down the street or when in his bathroom, and each time he laughed at it.
Since 1973, he has watched Monty Python and the Holy Grail 15 times with audiences and every time the part that gets the biggest laughs is The Black Knight.
It was also the part that all the producers wanted to cut because they thought it was going to offend people.
Similarly, when he made A Fish Called Wanda, he did test screenings and they would fill in evaluation cards.
The 3 funniest scenes were:
Killing the dogs
Otto eating Ken's fish
Otto being steamrollered by Ken
Meanwhile, the 3 most offensive scenes were:
Killing the dogs
Otto eating Ken's fish
Otto being steamrollered by Ken
Cleese's theory about why Black Humour works was that it deals with taboo subjects. While all humour can seem unkind - because you are laughing at humanity - in Black Humour there is some anxiety around these subjects.
For some people there is a lot of anxiety around these subjects. They are offended, and think others shouldn't make jokes or laugh about them. However most people have only a tiny bit of anxiety.
So if you make a good Black Humour joke you get the most laughs - you get the laughs you'd get anyway, and also the extra laughter which comes from the extra energy which is the anxiety being released when people laugh at the taboo. This is why he loves Black Humour.
In my summary, complaining about offensive humour is besides the point, since the offensive aspect is what makes it more funny. Indeed, I assert that if you get rid of offence (or potential offence) you get rid of humour - the only inoffensive jokes are puns.
The one word he used to describe Monty Python was "silly".
Personally I'm not a fan of the Flying Circus since much of it is a puzzling non-sequitur. However I did appreciate the fish slapping dance: