This is true but the common implication, "UX research knows your customer" is horseapples. I will point out we allow ourselves to believe that UX research knows the customer because we train like the above. We tell our engineers they don't know what the customer wants and when it comes time to put a foot down, they have nowhere firm to stand.
I _think_ it's the best we have right now, right? Excellent UX research speaks for itself, there's just not much of it. As an industry, we've done a realllllly good job of devaluing high-quality UX research and those who do it for a living.