I suspect it stems from a feeling of fairness: I have to follow the rules, so how come you get away with doing whatever you want? That's intuitively not fair.

Now I don't agree with that from a consequentialist point of view, but I could understand the feeling.

If someone has no real talents apart from following and enforcing arbitrary rules, he/she can rise in the social hierarchy by virtue signaling and reporting others. We see this in many open source projects now.

It's probably some form of crab bucket mentality. Many follow their paleolithic urges when it comes to watching others succeed.

I'll be the first to admit that it takes a little bit of conscious effort for me to look at another person leaving me in the dust and thinking "wow that's awesome. good for them".

Attempting to reframe my own comparative lack of success in terms of "they must have broken the rules or something" is a thing I reserve for competitive video gaming where the likelihood of an actual cheater is very high and the consequences of being wrong in my accusation are zero. Even if I totally delude myself into thinking everyone is using an aimbot and it has nothing to do with my shitty aim and I wind up the worst gamer on earth, I still have the rest of my life to work with.

In my personal experience, when you make your whole existence about winners breaking the rules and you being a relative loser because you follow all the rules, you turn into a monster.

> I find it super interesting that people want to get other people in trouble over (often) things that don't negatively affect them

I find it super interesting that people don't see a gradient here.

On one extreme, you have something like crossing the street against the light when nobody is at the intersection. On the other, you have all sorts of horrific things done to other people.

I'm pretty sure that the bulk of people in wealthy societies would intervene against "rule breakers" well before the horrific extreme. But where they start having qualms is interesting, and where you get all sorts of negative group behaviors, and that point will start to drift in response to how members of the group behave.

> I find it super interesting that people don't see a gradient here.

People tend to divide rules into 2 buckets: Ones that are inviolable and ones that are silly. It's like the old joke that "everyone who drives slower than me is an idiot, and everyone who drives faster is a maniac."

In tight-knit homogeneous societies, this leads to a set of "unwritten rules," but in less well-connected or less homogeneous societies, this leads to quite a bit of friction and people harassing each other. My friend is a cop and he gets called to a lot of apartment complexes where there are two cultures abutting each other (e.g. Mexicano and non-hispanic) and it's just both sides calling the cops on each other (in his estimation) not out of racism, but because they disagree on the unwritten rules. Then as each side becomes more convinced of their moral superiority (because we obey all the important rules), the arguments become more and more petty and ticky-tacky.

In a society with rules and such, if you're in a battle for social dominance, the rules are your best weapon.

You just need to find a way to create a narrative painting your opponent as a rule-breaker. Evidence needs to be interpreted appropriately, etc.

"If you're in a battle for social dominance" is key, of course.

Consider the present popularity of "victimhood".

>> what compels people to report rule breakers

they still believe there will be consequences to the rule breakers as a result of reporting them...

For some kids this just means they trust that the rules are there for a very good reason, and so are intrinsically good to follow. As a parent one hopes that your kids come to see your rules in that light, rather than as a tool to exercise power or maximize personal convenience, or any number of abuses.

The tricky rules are the very non-obvious ones, like those involving seat belts. Insurance against very infrequent events are difficult to motivate, and require a sophisticated understanding of risk to not seem arbitrary. (And given the number of baby-boomers who managed to survive childhood despite being thrown into a large back-seat with no seat-belts at all tells me that these rules might not be as wise as we think!)

Reporting rule-breakers is, of course, slightly different because now rule-breaking is not intrinsically bad, but extrinsically good to the person doing the turning in. (The motivation must be power and indirect punishment, and not compassion, because otherwise you'd talk to the rule-breaker first.) This is a favorite weapon that siblings naturally wield against each other at a very young age. That is the perversity of it rules, is that a human's first innocent instinct is to abuse them to harm a sibling. Ain't that something?