This kind of cr@p is inescapeable with nannies and maids.
Remember when they used to all be Caribbean? In Canada in the early part of the century they developed a program to bring specifically Caribbean women to Canada to act as maids (so liberated Canadian women could get out of the house to make some money; it was much cheaper for the gvt than providing child care). Since they were neither citizens nor tourists nor regular guest workers nor immigrants, we didn’t have to worry about petty things like paying them a living wage and ensuring their human rights are respected.
(A very interesting article about this is here - caution, not a PDF but a very slow-loading Word document)
Then in the 1970s the women started to fight back against all this (bouyed by the Civil Rights movement, I expect) and people started wanting more docile maids, and the legislation changed to allow women from anywhere to come (while simultaneously placing more and more restrictions on them), so Philipina maids became more common.
Now, people call up agencies wanting maids of specific national origin (and gender! How many male nannies have you ever heard of?). The agencies are just meeting the demands of many of their customers.
It also has to do with how much the women in question are willing to accept in wages - clearly, one could hire an undocumented Hispanic woman for substantially less than a native-born American woman (because the American could get much more elsewhere, and the Hispanic couldn’t - even if they have the exact same skill set). There are similar gradations among most ethnic groups that come from nothing more than subtle prejudices in mass numbers of individuals who make decisions whether or not to hire people and at what wage.
Disgusting? Yes, absolutely. But the deep historical and global precedent to all this is even more disgusting.
(My cite: I did my thesis on this topic and read all this stuff a few years ago, plus more that would make your hair curl. I still have references if anyone cares but I’m at work right now and couldn’t get them until tomorrow.)