In this novel, dating isn't just a game – it's war. The demure Miss Bart thinks of Percy as her "prey" and "organize[s] a method of attack" while on the train to Bellomont (1.2.8). Her beauty is described as a "weapon" (1.3.57). And check out this passage, re: the Brys' entry into the social elite:
To attack society collectively, when one's means of approach are limited to a few acquaintances, is like advancing into a strange country with an insufficient number of scouts; but such rash tactics have sometimes led to brilliant victories. (1.12.7)
It's not all tea parties and expensive upholstery. This is serious stuff. Consequently, however, the causalities of such social warfare are similarly grave. Lily becomes a tactical "sacrifice" to the Dorsets' marriage; it's clear that Bertha Dorset uses her as a pawn in her own scheming games. Sounds like more objectification, and more social Darwinism (survival of the socially fittest, right?).