The leader who answers every question with “because I said so” will eventually be the only one who believes it.

That answer works for as long as people have no choice, and it builds nothing. Every time a rule gets enforced without a reason attached, the rule loses a little support, until the only person who believes in it is the one repeating the phrase. Explanations are what let a rule survive being inconvenient.

When somebody asks why, treat it as a fair question even when the timing is bad, and give the reason. If you do not have one, say you will go and find out. Rules people understand hold up without you standing over them.