The Indian Constitution devotes an entire part to define non-binding Directive Principles of State Policy likely influenced by the Irish Constitution. They were meant to guide governments in the implementation of policy and provide a yardstick to the electorate Khanna, Hans Raj. Making of India's Constitution. Eastern Book Company, 2008. Page 80.
Since they weren't enforceable, these principles seem to have been incorporated into the Constitution based on individual directions that the framers found desirable, without significant scrutiny. Thus, it seems like these principles provide guidelines that are arbitrary or antiquated, and do not reflect the democratic will of the people. For instance, Article 48 is used to justify a ban on cow slaughter, which reflects a particular worldview that reveres cows.
Is there any evidence justifying the inclusion of any/each of these principles in a Constitution? Does the political experience of India, Ireland, Nepal etc. suggest that governments that do not follow these principles are punished by the electorate (has it ever been a "poll issue")? Are there any parallels in other Constitutions of having unenforced guidelines (let's ignore the Pirate code)?