The parent’s point was plainly that bias is unavoidable and making it overt is realistically all we can do. It’s a pragmatic take, albeit overly terse. They could have additionally included something like “and try to minimize its effects” sure, but that to me was implicit. I may be reading that fairly charitably, but perhaps that is just my own bias. I certainly have a bias to judge it more charitably than I do someone who leaps straight to moral outrage and judgement this early in the interaction.
In this case, I simply felt your judgment of the parent wasn’t fair, and showed a moral bias. Maybe they weren’t perfectly clear, and too absolute, but your response wasn’t proportionate either. It condemned more than it understood. I interpreted it as an epistemic observation and you interpreted it as an offense. The very fact that we came away with two completely different readings of the same short sentence rather proves the point.
Thank you for putting words in my mouth regarding my definition of the word bias, but lets use your own: "Bias is a distortion from reality and truth." If that is the case, we can never hope to avoid it, because we will never have perfect information. Using that definition, we are quite literally constantly in a state of bias. Your very own definition is far more broadly supportive of the notion that bias can't be avoided and consequently suggests bias is effectively ubiquitous. This to me is the primary point the parent was making.
I was perhaps too charitable, and you not enough. We are both biased, and going by the advice of the parent, I'm pointing it out. I don't think there is much more I can do.