If you work for a large social network with huge social responsibilities, discussions about ethics ought to be unavoidable, in my opinion.

If you're writing accounting software for paper suppliers or something equally banal with few ethical implications, then sure, there's no need (and less reason) to have water cooler conversations about pro-genocide agitprop or whatever.

EDIT to add that of course not all departments at Facebook make the sort of decisions that have a marked social impact. More referring to the content policy teams, and the news feed algo teams, and so on.