Imagine this:
You have a society of humans. There is a relatively low crime rate, but it's overwhelmingly peaceful and nobody lives in fear or paranoia. You can even leave your car open and bike unlocked.
Now add to that orcs, so much that 13% of the population are orcs. Orcs are more violent and aggressive, and are often unreasonable and impulsive. They have their violent ways like trial by combat and duels to the death, so their murder rate is extremely high. They mostly kill each other, but that little bit that spills over to humans (with a culture like that, that simply happens) by far exceeds what they normally had.
Orcs are only 13% of that population, yet they make up 60%+ of all murder cases. Which means 87% of the population causes 40%- of all murders. Math: 40/87 = 0.46; 60/13 = 4.62. Which means the murder rate of orcs is 10 times that of humans. And it also means that by only adding orcs to the population the murder rate doubled, possibly even tripled.
Even if only 10% of the orc murders hits humans, it means the rate of them getting murdered doubled. 10% of 4.62 is 0.46, so 0.46 of 0.46 is ~+100%. This alone is not trivial.
But murder is not the only thing orcs do. They also like to provoke, are aggressive, violent, impulsive, like to gang up, like to steal bikes, rape, gang rape, litter, shout, be needlessly loud and annoying, hear loud music in the bus, and are generally VERY stupid up to a point humans cannot even communicate with them. So even if you accept the 10x murder rate per capita as a baseline risk, there is a 100x rate of them causing trouble, and when they do, interactions (even via police) are a menace, making it 10x worse, as they like to escalate even the most menial of things to the maximum.
And they are unproductive, have 0 geniuses, are on welfare, and the taxes you are forced to pay feed them to breed. So your boundless tolerance, and you are asked to tolerate A LOT, is rewarded with death, a lot of extra exploitation, ungratefulness, hatred and having to live among (or flee from) a parasitic menace.
Orcs = niggers btw. What do you mean how I would feel if I didn't say nigger this morning? But I did!
