It's interesting that class prejudice is exclusively expressed as a racial issue these days.
I'm not claiming that's the case here (I have no idea if these "riders" referred to in the article are mostly immigrants or not), but it is certainly a common phenomenon.
There are plenty doing the exact opposite and insisting that all racial prejudice is somehow class based and that "class solidarity" is somehow the natural state of the world. Including infamously demanding that racial minorities basically sit down and shut up because their problems are a "distraction".