I had a brief exchange of messages with a British Muslim bloke on social media who had asked me, very politely, why I had posted a picture of the Star of David with the words ‘I Stand With Israel’ underneath. A good question, really – I more usually think this kind of keyboard-warrior grandstanding embarrassing and self-promoting, all that light-a-candle-we-are-the-world- Je-Suis-Charlie cant.