I can’t imagine people being mad about a black Vulcan or female captain!
It was a loud minority. People who didn’t understand that Star Trek has always been about diversity. The “Vulcans aren’t black!” people were especially silly. I kept saying to them, “how many Vulcans out of the billions of Vulcans out there have we actually seen?” And TNG already had women who were admirals, so the complaints about Janeway were silly too.
It’s the usual conservative contingent of Star Trek fans who ignore everything that makes Star Trek what it is in favor of pew pew space battles.