WARNING: REALMS OF RUNETERRA SPOILERS AHEAD
The old Shuriman Empire killed the disabled. That's it in a nutshell. The book has a brief mention of the Baccai, failed Ascended, and says "it was considered a kindness to end their inhuman sufferings as quickly as possible." It does NOT specify whether the Baccai were consulted before being, you know, murdered.
This can go one of two ways:
1. Baccai consented to being killed. Maybe they were in severe pain (though it's unlikely that applied to every single one of them), or maybe they believed they had no value as people because _that's what their culture said._ They failed Ascension, the greatest test there is, and therefore are worthless. Result: Baccai absorb toxic, dehumanizing values and commit suicide by proxy.
2. Baccai did not consent to being killed. They were murdered as a "kindness" whether they wanted it or not. Result: Ancient Shuriman culture says killing the disabled AGAINST THEIR WILL is actually a good thing sometimes.
And make no mistake, these guys _are_ disabled. The source is magic rather than injury or birth, but ultimately Shurima is killing a disabled subsection of its population. There are plenty of ways to be "kind" to disabled people without killing them. Those are called "accommodations." If the Baccai have trouble walking, get 'em some crutches. Soldiers lose limbs all the time, there's no way Shurima doesn't know what a crutch is. If the Baccai are in pain, get 'em painkillers. Shurima has no shortage of mages, there must be some kind of spell or herb that makes stuff hurt less.
But Shurima decided that accommodating the disabled just wasn't a good option and killed them instead. You could say that's symbolic of IRL devaluation of disabled lives, but right now I want to focus on Shurima specifically. Speaking as a disabled person (though not by magic), screw those guys.
Then again, they also had slaves. Probably shouldn't expect a lot of morality from them.