Well, yeah, you can say the timing of the showing wasn't great, I can agree with that. But that's hardly Chris Morris responsibility.
Can't remember the running joke about Jewish people, but what, are we saying you can't make a film about fictional events where something factual happened? I don't get that. I missed out on arriving at Kings Cross around the time of the bombing by twenty minutes, but I don't have a problem with it. In fact, I never even thought about that when watching the film. And also, the point of the film, I think, is that suicide bombers may be suicide bombers, but they are also real people. Sometimes these real people are also idiots, with families. Families that are just affected by their actions as victims (and their families) are.
Your rationale for not liking the film reminds me of men in their 50's who just take against something for no real reason, but then start inventing reasons for not liking it. Like my stepdad and the Simpsons and like Jo's dad and any meal that doesn't include potatoes.
