You're supposed to notice differences, just not act unfairly because of them, to pre-judge someone, to show prejudice because of a trait which is not clearly and demonstrably related to whatever the matter is about. This gets tricky because in between the two extremes, absurd and reasonable, is where everything happens. I doubt even the KKK considers skin color relevant in deciding whether or not someone enjoys Ice Tea, alternatively you really have to have your head in the sand to be surprised when your friend Brigham seems a bit confused and ungrateful that you bought him an espresso maker for his birthday, or why your friend Achmed keeps declining your invites to rib cook-offs. So we limit this to intentional or even unintentional acts of harm to other people based on unreasonable and unfair discrimination... we've never discouraged people from observing traits and using them to draw reasonable and fair conclusions off of, that's more or less what thinking people do. Profiling and discrimination are at the core of rational thinking.

When we talk about everyone being the same, and we push that point to discourage noticing or thinking about those differences, we're essentially electing to fight ignorance with... ignorance.

That doesn't make much sense.