Everyone must follow the same rules
It has been a point of frustration for many years that the establishment does not hold itself to the same standard as the masses. Part of the Contract With America in 1994 was to make Congress obey the laws it passes, and that was still a problem two decades later. A key part of our civil order is that we are a nation of laws, not men. When people believe that is not the case, civil order starts to break down.
With that in mind, here is a very good point by Doug Wilson:
Every social order depends in a foundational way on self-governance and voluntary compliance from the vast majority of the population. This is why one of the worst things that a ruling class can do is behave in such a way as to foster in the population a contempt for the law. What they are actually doing is making the law generally risible, and thus destroying the only thing that supports them in their station.
We have seen this problem highlighted under rules meant to contain the COVID-19 pandemic. From elected officials not following lockdown rules that stop their constituents from earning a living or being caught without wearing face masks, to giving their close contacts special access to testing, much of the frustration over pandemic mitigation policy is the "ruling class" not following their own rules.
The same applies in the church. The reason it is so harmful when church leaders are caught in serious sin (or even worse, criminal behavior and abuse) is it shakes the faith of Christians both under their authority and in the church at large. It also gives the world an opportunity to mock and scorn, using the failures of church leadership and/or prominent Christians to attack the standards these men have betrayed.
This is why leaders must first lead by example. This is true in the political sphere, the church and the home. Those being led must see the leaders as following the same rules - ideally with even more dedication. Those who seek to be in authority must first demonstrate they are willing to be under authority.