The reason why "ethnicity" is generally seen (note: "generally seen") among those who study humanity is because "race" is a misnomer. Humans *are* all the same race, in fact, we're 99.98% genetically identical. "Race" is a term for a much larger separation than that. Also, ethnicity makes the reference to a skin colour and potential ancestral culture (rather than birth culture) which is often what people are referring to, rather than a genetic dissimilarity or a birth in a country or even participation in the perceived culture (ex: not all black people are from African countries and cultures, some are quite canadian/american).
Ethnicity is a major factor in social class, and in financial class. A minority race, member of a minority religion, non binary or gay sexuality, all of those can impact social class.
That's why it gets sticky, because tax brackets (financial class) are separate from social class (perceived worth) and those in turn, are separate from showing taste and tact ("having class").
As well behaved as a (again example) black man may be, and as wealthy as he may be, he will have had barriers his entire life for access to education, treatment and employment opportunities. Add in something like being trans, or muslim, and he's pretty much stuck getting maybe a third of what a white middle aged cis male would in pretty much every arena.
All forms of the mentioned types of class affect how much treatment and how much respect you receive in everyday occurrences, let alone access to healthcare and the opportunities for a stable life style.
If it helps, perhaps it would be good to think about it as someone's social identity and where that would be placed in society's eyes-like your therapist would be well off, white, jewish, cisgender, male. They recieve much better treatment and are so seen as higher social class than a well off, black, jewish, cisgender, male. Thus a social "class" that's not necessarily financial, but financial is a part of it.
As much as cosmetic brands may wish, we still have yet to have something to make someone caucasian is they're not born pale skinned to begin with, money truly, cannot buy everything.
I think I'll leave this thread now as is, with the simple statement that *yes* social class *most definitely* impacts your treatment, recovery and even diagnosis, and having done what I can to clear up the idea of a complex issue such as "social class".