Very true - technical companies (like smartwool) tend to use merino, but that doesn't mean all merino is technical wool and may require more gentle care than say, Smartwool socks and base layers, which can even be thrown in the dryer. Do that with a merino sweater and you'll probably find it a suitable size for a 6 yo... not that you cannot wash wool. I have a nice cashmere-silk blend turtleneck that I wash often. I just make sure to air dry it. Unlike the wool of old times, it is thin, soft and dries quickly.