I'm trying to follow your point, and I can't follow it at all.

What I understand the OP to be arguing is that "white feminism" is not a useful term because it doesn't describe a concept with material reality. It describes an emotional sense of exclusion. It is used in practice to group a set of women together on the basis of an externally perceived identity rather than an understood shared set of unifying experiences. Furthermore, it is used to rank those women in an hierarchical mode in a lot of spaces, which contributes to silencing. Off the top of my head, immigrant women from Eastern Europe, Jewish women, light-skinned Latinas, light-skinned Arabs, rural white women, white women without college degrees, and white lesbian women are all women who can get grouped into white womenness but who won't necessarily share the life experiences, advantages, or cultural norms that get described as "white women."

As far as I've been able to track it, the term "white feminism" arose as part of a power struggle among the early generation of Internet blogging feminists (specifically out of a conflict on Feministe between Amanda Marcotte, Mikki Kendall, Flavia Dzodan, and some others that I can't remember off the top of my head.)