I'm merely informing you that the definition of race has improved since the 19th century when everyone was either Caucasian, Negroid or Mongoloid
I don't believe in either of your claims: neither that the definition has actually changed, nor that the change you assert would've been for the better, had it actually happened.
Race is most certainly not a "social construct" — the very reason, discrimination based on it is wrong (and illegal) is that it is immutable. A human being does not choose to be of particular race.
Now, there has always been the other meaning for the same word — a homonym, really — which would, indeed, make any grouping of people, including fans of a particular sports team, or cat-lovers, or Emacs-users a "race". That meaning is not at all new — it certainly existed in the 19th century — but it, quite clearly and self-evidently, is not what the anti-discrimination laws mean. A FreeBSD-bigot like myself can not claim "racial discrimination" after being turned away from an all-Windows shop, for example.
I'm not too familiar with the case [of Rachel Dolezal -mi]
Of course, you aren't — Blacks are given a pass by all your news-sources, when they discriminate or even murder based on race.
she resigned from her job because she had been caught lying about her background
Obviously, had she not lied, they would not have hired her in the first place — even though she was, obviously, qualified — it is Ok, for some reason, for Blacks to discriminate against Whites.
We try to fix this over time, but some people think that going back to the 'good old days , whenever they were supposed to be, will solve all of this.
What? Does this, somehow, justify the discrimination against Whites and Asians manifested by NAACP?