This is a sound explanation and a huge part of it.
Furthermore, when we see that dog we can only see a dog. Not a brown dog, not a white dog, not a Muslim dog, not a Russian dog, not an anti-abortion dog, not a liberal or conservative dog.
We put people in boxes because it makes things simpler and saves times. It also utterly fucks up society and mires us in perpetual conflict and tragic misunderstanding.
I might see dead Palestinian children and see dead children, the worst sight eyes can see. Others might see unfortunate but necessary 'collateral damage', some may even see dead 'future terrorists', others simple 'dead Muslims'.
There's a reason most observers from countries outside of the USA see the American police force murdering unarmed civilians, disproportionately black Americans at at least 5x the rate, and see grotesque tyranny while Lectoyo and others make vulgar facetious comments about how they were "perfectly innocent", implying that they deserved to be publicly executed without trial if they had any sort of legal infraction.
You have to be neck deep in the politics of division to see yet another victim of police tyranny and say "He probably had it coming, I bet he'd broken some sort of law" when the sober outsider says "They're unarmed which means if you kill them, you've murdered them. There is no crime that carries the punishment of public execution without trial. This is appalling".
The dog carries no such equivocality. It could bully a postman, it could bark too loud, it could even have bitten someone - it's still just a dog, not a thug, not a n*gger, not an Islamist, not a whore. Now when people can view a dog as "just a fucking animal, who gives a shit" then they just seem evil because 'we' at least give ourselves reasons as to why a dead victim had it coming.
For the record, those who say "I like animals more than people anyway because people are horrible" are horrible people if they lack compassion for human beings based on this. They're too ignorant and foolish to see that THEY are the uncaring cold dead inside human to everybody but themselves. Hitler thought animal testing was barbaric so he tested chemicals on Jews instead. If you think humans are too cruel then don't be one yourself.