John Cleese was undoubtedly one of the most brilliant and original comedians of his generation, and would have been remembered as a legend of intelligent wit and original script had he simply not devolved to be so full of hate recently.
Sadly, as he reaches his ninth decade and hence in what is most likely the last years of his life (and perhaps his age is an excuse...), he has become a bitter xenophobe spouting the most crass anti-Muslim stereotypes and regurgitating the worst caricatures of our faith that the Far Right can come up with. For the last few months, he has been on a literal crusade against Islam, and seems to refuse any sensible engagement with Muslims online or in person.
But Cleese is (or was) too intelligent to believe such lies; a simple dialogue or search would clear up these misconceptions. It's obvious his emotions have gotten the better of his intelligence.
To answer this simple garbling of facts:
No one is saying that the early Islamic empires expanded through friendly persuasion alone; they politically expanded through military conquest, just as virtually every major empire in history did. The more relevant question is whether people were converted by force. On that point, the historical evidence is quite clear. Egypt, Persia, and other regions remained largely non-Muslim for centuries after conquest, while the world's largest Muslim populations today—such as Indonesia—became Muslim without invading armies. So the historical record points to a distinction between the spread of Muslim political rule and the spread of the Islamic faith itself. Any fair assessment should recognize both.
More importantly, are you willing to apply your critique to your own civilization? Have you forgotten Britain's colonial history, and its boast of having an empire on which the sun never set, controlling over a quarter of the earth's population, subjugating hundreds of millions of peoples and fleecing the economies of many civilizations by force? Not to mention the entire mess of the modern Middle East...of which the lion's share is the direct fault of Britain with its Sykes-Picot agreement and Balfour Declaration?
All civilizations acted with a level of political force to protect their interests, but some left greater and more noble legacies than others.
Two hundred years after Mohammed's death, a Muslim army got half way up France before it was defeated
Islamic armies had already invaded North Africa and Spain and large swathes of the Middle East
Do you really think that was achieved by friendly persuasion ?