1) Stedman and de Botton are widely agreed to be - in politest possible terms - flawed.
2) The diplomat camp is reading them charitably, focusing on the things they say that are correct, and attempting to find common ground so that atheism can present a unified front.
3) The firebrand camp is calling them out on their accommodationism, so as not to cede ground to religion.
I've wrangled with this a bit, but, as usual, have come down on the firebrand side. I'm an ex-religious person. One of the biggest reasons that I left religion was realizing that the values about it which I embraced were, in fact, independent of the belief system. Even Hemant at Friendly Atheist says that de Botton is "...basically throwing secular values under the bus for the sake of making his point." WE CAN'T LET HIM DO THAT. Above all, we can't let the religious side - in this case, speaking through de Botton - frame the debate, or we've already lost. We can't concede these values to religion, and then try to reclaim or rebuild them. Fuck no. This imprecise language just bolsters religious belief, all religious belief, any religious belief as the source of morality, and relegates atheism to a second-class, impoverished philosophy that we all (except for Stedman and de Botton, apparently) know it's not.
I know this language that Stedman and de Botton are using. They're speaking Christian - it's my native tongue. It will only make the religious more confident, only make them pity us more. We can't play into their myth about us - we have to draw a line and show them the reality of atheism and morality.