Your interpretation of that statement makes no sense. With that interpretation: a) the bar isn't lowered in any sense of the word, as that would imply less qualified people getting in, b) you'd claim that for unexplained reasons, Google can give more accurate evaluations for diversity candidates, c) and/or that they are rejecting candidates they know unequivocally to be qualified and d) even if all of this was the case, there wouldn't be anything discriminatory about it. At least where I'm from, it is literally a legal requirement, that if multiple candidates compete for the same position, diversity candidates are given preference.

Even in its most generous reading (yours), this sentence makes zero sense.