Truth, Fiction, and Losing Sight of What's Important

As an atheist, I don't care when religious types claim some interpretation of their faith is "not true." After all, this behavior has been with us since phenotypic diversity in Scotsmen [1].  We know very well what the speaker means.  X is something they don't like, and they don't want it associated with Y (usually themselves).  If for some reason an atheist took that claim literally, it should be a mere redundancy, eliciting the response "Yes, of course, that version too." However, some atheists have been taking the claim too seriously. And I find that I do care when atheists waste time combating this well known fallacy, and (more baffling to me) try to argue what interpretation should be considered a believer's "true" faith. This activity suggests they have lost sight of what is important, as it often undercuts efforts required to achieve real, secular gains. Current events have made this a relevant issue to discuss, as it raises (to my mind) a moral question for atheists operating as public intellectuals.

Steven Weinberg versus science-based morality

In 2012, a number of well-known scientists and philosophers gathered for a weekend to discuss hot-topics or unresolved issues within naturalism.  Basically they were trying to scope out and/or develop a more coherent world-view from a strictly scientific/materialist perspective.  The entire series is still available online and worth watching if you missed it.  

One video is dedicated to their discussion of morality.  To my surprise Steven Weinberg, a physicist, presented a solid argument against so-called science-based moral theories.  His portion begins about 7 minutes into the video, and he remains pivotal to the remaining discussion.