Just speculation, but I think -- like the Americans -- the "right wing" French have been more openly anti-immigration and anti-Islam than the English for awhile, so there's less desensitization that needs to take place to get the French populace on board against leftist rot. The English are still largely hamstrung by performative civility, just like my fellow Canadians.

Edit: I want to add that while I think the proportions of the population against leftism in each of the UK and France are about the same, I think the Overton window has progressed further in France.

Just speculation, but I think -- like the Americans -- the "right wing" French have been more openly anti-immigration and anti-Islam than the English for awhile, so there's less desensitization that needs to take place to get the French populace on board against leftist rot. The English are still largely hamstrung by performative civility, just like my fellow Canadians.