It portrays a serious extremist group being derailed by the demands of the furthest, most boundary-obliterating, most ludicrous social extremists imaginable at the time. The fact that that group was later considered centrist doesn't make the joke PC, it just means people don't get the joke anymore.

> Nothing about Monty Python was unkind

"Never Be Rude to an Arab" is Islamaphobic on its face, as well as normalizing other racial slurs.

"I like Chinese" is full of pretty gross stereotypes as well.

The troop claims they harbor no ill intent, and that may be true, but it's easy to say "We're not here to offend" about someone else but not acknowledging the power differences here and why someone might be offended.

We can only behave according to what is acceptable in the present moment we happen to exist in, it would be unreasonable to ask people to attempt to predict future morality when making ethical choices. We can try to make a good guess about it and act accordingly but it'll never be perfect, nobody can make a ruler with units that don't exist yet let alone try to measure something with it. I think intent counts in these situations too, like you say Monty Python never set out to be unkind or bigoted to anyone.

Would it be an acceptable sketch today? Probably not, and that's not really a bad thing given that improvements to the rights and recognition of transgender people is one of the more positive things to come out of the last couple of decades in my opinion. Should Monty Python be cancelled over this sketch though? Not in a million years.

That's the complexity. The Roman invasion did enrich their society (as did the Greek before), yet all none of the dead people got any of it and many individual lives were completely destroyed even if not literally terminated.

And the joke applies almost exactly to the British rule of their colonies. Or do you think Monty Python wouldn't make an anti-nationalist joke?

(The "let's interrupt our program because the Queen has just started watching" is the best.)