I think that is not a logical comparison and ignores part of
@MGibster's post.
Do you imagine half-elves are a people with their own communities in your fantasy world or are they uncommon/rare individuals that fit within the fabric of society they live in i.e. different but same.
They certainly DO NOT have their own history, customs, religion and language like the Jews and Roma you compared them to.
This was such a weird comparison to make.
IRL, for example, you could be half black and half white of any kind- Barack Obama is half Kenyan and half white American, for instance. He's just a half black, half white guy; he was definitely raised in the racialized culture of America, but he doesn't belong to a "mixed race culture." In this example, he's your regular half-elf.
On the other hand, you have
creole cultures that do result from two or more peoples (usually of different races) coming together in a geographically bound region and creating their own culture. There may be Louisiana Creoles who look very similar to Barack Obama and have almost exactly 50% black and 50% white ancestry, but they have a totally different culture that is based in part by most members of that community having black and white ancestry. In this example, the Louisiana Creole are akin to the Khoravar of Eberron.
I want to take a moment to point out that yes, Creole cultures do have their own history, customs, religion (ever heard of Louisiana Voodoo or Santeria?) and language (including "Pidgins") like the Jews and Roma do now. You just engaged in a flagrant and frankly disgusting example of cultural erasure and you should be ashamed.
EDIT: Also for my personal fantasy world; I have both. In mine the elves are immortal and their governments have strict population control and forced sterilization of the underclass, so half-elves are explicitly children born outside of the "system" and the reach of the elven governments, often kept stashed away in other countries. They are typically the children of male elf diplomats and traders, and there are cities close to the borders of elven nations where lots of elf high society go to naughty word and enjoy luxuries (if the elves are Chinese, think of places like Macau, or how Saudi Arabians drive over the border to Bahrain or Dubai to get plastered), so these cities have developed large high elf communities over the last few centuries that are starting to generate their own artistic and cultural identities.