Many times after making inferences about a person, I was admonished not to "judge" by some well-meaning figure of authority who would often follow up on this with "you don't know what they're going through." A variation of this is "don't judge a book by its cover." "You can't judge me" was a typical celebrity line.
Strangely, I can't even recall seeing discussion of this attitude on the internet. I'm not sure why since it was extremely prevalent not too long in the past, but if I had to guess, it's because it was a saying from the "colorblind" times. Obama and his ilk kicked off a new era in racial politics where it became permissible to judge white people for everything they did and said, so even a white lib can't really tell their kids "don't judge" when they are teaching them to constantly judge themselves for white attitudes like speaking clearly.
The notion of not judging comes from Jesus' words in Matthew 7, "Judge not, lest you should be judged." These words are taken at face value and ripped off in simplistic and tendentious ways, but the Bible is meant to be read as a whole, not quote mined, and the full meaning is closer to "don't judge superficially." GotQuestions has a great article on the topic. Indeed, Jesus also said, "Stop judging by mere appearances, but judge correctly."
So the Bible does indeed tell us that snap judgments are wrong. But it also calls on us to investigate, discern, and make more accurate judgments. Without the ability to do this human civilization, and worship of God, would cease to exist.
I'm not sure how many parents are still repeating "don't judge" to their kids, but instead of an easy (and frankly hypocritical) hit of virtue signaling, maybe it's better to explain to them that they should keep their cool and take the time to judge accurately. Sometimes a book is indeed different from its cover, but other times the cover is exactly what you need to know. Ignoring abundant evidence from reality is not practical or Biblical. Case in point.
It's been translated over and over, and at best we can get a couple varied versions and interpretations. Humans are fallible, after all, and humans made those copies.
I prefer the life lesson of telling a kid "never judge a book by its cover, everyone says that." and then showing them "Math for Grade 3", and asking them what's inside it. The correct answer is elementary math, because people are lying to you. Judge things based on their covers, that's why covers exist. People, too, present themselves in specific ways: A woman in a wedding dress is probably going to a wedding, not a funeral. Judge. Judge as much and as often as you can.
But remember that even though everyone is saying "never judge a book by its cover", those same people made that cover. They, too, judge based on covers. Everyone does. So make sure you're presenting well, too. They will judge you based on your cover, just as you judge them on theirs. "Judge not, lest ye be judged" is crazy, because you are ALREADY judged. It's on you to be aware of it.