Similarly, and this should be scary to anyone who cares about epistemic rationality, suppose you have various false beliefs and you decide that those beliefs are so important to your identity that people who don't also believe them can't possibly love you the way you are, so you only surround yourself with people who agree with them..

Sure, in such a case, I've optimized for my own 'social harmony'. We all do this to varying degrees anyway. Signalling, sub-cultures and all that blah. Note that the quote simply speaks of a process (selection) to maximize an end (social harmony, however that is defined). It doesn't say anything about whether such selection should be for false or true values (however these are defined).