The original point was in-depth discussion of things like dietary restrictions necessarily come to political questions. The counter-argument seems to be "don't discuss anything in depth."
I showed my SO this thread and she laughed at the notion that she apparently can't discuss her lifestyle (she takes a car to work and drinks tap water, too) without it being political.
I suspect, as another commenter said, that this is apparently a cultural aspect where I and those around me have always grown up talking to people about such topics without any of them becoming political, while apparently others have not had such 'training'.