What they did is a hate crime regardless of whether they were primarily motivated by racial or ableist feelings. Either (or both) is enough for that label. We probably can't know everything that went into their plan just yet though.
"**** white people" is no different than saying "**** black people" or "**** Hispanics" or "**** [insert a race or ethnicity]". It's especially absurd to suggest that when they were cutting his flesh from his head and slicing his arms as they shouted "**** white people". I mean wtf.
On an individual basis no, there isn't a difference. It's prejudice regardless of what group you're insulting. But in the context of a country like America where white people generally have the advantage (in many ways) over non-white and blacks specifically, the impact of a white person insulting (or attacking) a black person and a black person insulting (or attacking) a white person are not necessarily going to be equal. The legal system, for instance, tends to give harsher punishments to black defendants compared to white defendants who are convicted of the same crimes.
Given the specific things the attackers said here it will be all but impossible for them to argue in court that there was not a racial element. There's not usually direct quotes from attackers so the motivations have to be inferred elsewhere. This is why I'm worried about the long-term ramifications of this, that it will be seen as the "normal" mindset of black people so that any time a black person commits a crime in the future and there is a white victim it will be viewed as a specifically racially based attack (or theft, or whatever). Specifically I worry that people in law enforcement/the legal system/government will have this view and it will bias their judgment, leading to disproportionate punishments. I don't worry so much about that happening in cases of white people committing crimes against black people though because law enforcement/the legal system/government is majority white in almost every case and they won't assume a racial prejudice by default when it comes to white criminals (because then they'd have to assume that they, too, have prejudice inside them).
So, like, the difference is one of an individual level versus a systemic level. It's equally bad to insult or attack someone based on race (regardless of the races involved) but the system will treat them differently.
Why is it worse to attack someone with a disability than it is to attack someone without? Even as a disabled person myself I don't understand why this is worse because of his disability. It would have been equally awful no matter why they did it or who they did it to.
Part of it is the assumption that disabled people can't protect or take care of themselves (which can be true in some cases) and we generally feel that attacking someone who can't fight back or escape or otherwise has no recourse is extra bad and/or shows some kind of elevated cruelty or evil in the mind of the attacker who chose, of all people, to attack someone who was not able to defend themselves. That's my take anyway. I think it's something that's pretty ingrained in people, but I'm no expert in psychology.
So when the crime is committed against someone and there is no personal gain to be had (or the gain is incidental, or would have been greater had they chosen a different victim) is feels like they were targeted for the above reason. That, or because of hatred.
Which is the other part, that there is a level of discomfort and prejudice and sometimes even hatred for disabled people in the minds of many. Like other irrational hatreds, they see disabled people as somehow being a factor or cause in their own problems and want to take revenge for it or otherwise lash out. I'm sure we can all find examples of things people will say about disabilities without any trouble so no need to get into examples.
