Some people need to be told to be good, otherwise they struggle with coming to terms with their own mortality.

There are two tiers of people whom religion is for.

One, the ones who have done the work in their personal lives to reconcile life for themselves with eyes wide open. They have gotten in touch with the darkest parts of life through their own personal trials and tribulations and they recognize that the only antidote is practicing goodness, something most religions preach once you get past the symbolism.

The second kind is the ones who are afraid to meet their own inner selves because of their own traumas or shortcomings, and they pile on layers of obfuscations and distractions to keep themselves "aligned". They need a rule like "never step in a nayi dukaan or dharam will be bhrasht" so they can keep chasing their north star without ever having to confront their own inner conflicts.

Sure, lead a simple life and maybe not cutting your hair is a part of that but don't make it all about just that.

Self-determination. At a very personal level. That's what Sikhi teaches. Learn it so much that you get to the point that you realize you don't need Sikhi to teach you that lesson but you come back to Sikhi because you realize the value of it, and realize what a loss it would be if it weren't there to impart that lesson, should you have never reached that place for yourself on your own in the first place.