If I don't trust my therapist, I can ignore them and find a new therapist.

If I don't trust my housekeeper, I can fire them and hire a new housekeeper.

If I don't trust a police officer, it doesn't matter. If they detain me and order me to step out of my vehicle, I have to comply under threat of the law and violence. I don't get to only listen to police officers whom I trust.

That is why they must be held to a higher standard, because they wield elevated authority not granted to ordinary citizens.

A police officer who has demonstrated such a reckless disregard for the law and safety can not be trusted as a police officer to uphold the law.

In general when the stakes are higher and the ambiguity of outcome is less clear, secondary signals become more important.

Concretely: I don't give a shit if my housecleaner doesn't make their own bed as long as they make mine; the outcome I need is easy to verify and the stakes are fairly low so the secondary signal doesn't matter very much. Conversely, I care a lot if the therapist I'm relying on to help me manage my depression is visibly unable to manage their own; the outcome I need has a slow feedback loop and the stakes are high so I'm much more likely to rely on secondary signals like "is this person able to manage their own mood successfully?"

Because those other examples don't involve breaking the law.

At the risk of pointing out the obvious: society holds breaking the law to be more serious than being fat or not making your bed.

Now, speeding is very much a lesser form of breaking the law...but then again, very few people have literally hundreds of speeding tickets.