ignoring the issue with Lutris and AI for a minute

Please by all means, I ignored it in the first place, I find this way more interesting.

If you choose not to judge your own actions by the expected consequences of those actions for everyone involved, then how exactly are you supposed to judge them?

Well, this is only half the problem. It's a bad system because it demands the impossible of you (i.e. accurately predict the future) but it also has a really narrow interest in the dimensions of human morality.

To directly answer the question however: you judge them by a set of principles, whichever you deem right, that you apply consistently across choices.

When it comes to inter-personal choices, the vast majority of all questions can easily be answered by asking yourself "am i betraying some explicit or implicit bond of trust with someone (who has not done so themselves) by doing/saying this?" and if you are, you just stop.

And to be clear, I don't claim to follow this principle 100% of the time, I am not a saint, but that to me is the guiding principle when there are stakes to my behaviour, and it has not failed me yet.

If you’re following some rule that disagrees with the utilitarian view, then by definition it’s a rule that in your own opinion leads to a worse outcome for everyone.

(Emphasis added)

At its core, the idea of utilitarian morality is to "maximise utility", that is to do whatever does the most "good" to the highest number of people.

This is, IMO, a terrible metric, and as a deontologist I am perfectly happy reaching a "worse" outcome by it.

It is not particularly hard to see how, by applying this metric, you can justify any kind of scapegoating, abuse, and/or undue leniency on people that would deserve harsh punishment in any deontological or virtue based system, as soon as enough "good" is produced through it.

There is a very dark, but apt, joke about this kind of approach to morality: that 9/10 people involved in it endorse gang rape.

To me, morality is a qualitative assessment, not a quantitative one.

It does not matter how many perpetrator lives will be ruined if they have earned their punishment, and it does not matter how much happier they would be to get away with the crime than the victim would suffer, comparatively.

To do anything else would be to relinquish morality to the whims of the masses, because it implies that there is a threshold past which the abuse of the few becomes negligible due to the benefits it brings to the many.

trying to claim that all utilitarians are either stupid or evil is just incorrect.

To be fair I also stated they can be naïve; I was one too in my youth, until I learned and understood better.