I'm sure Judd did say that. My own borrowed/paraphrased version is "Simplistic is easy to do; simple is hard."
And gobsmacked is from the article: His own home was small and extreme, with two benches and a table, a wooden sofa-cum-day-bed, one long clean neat stainless-steel surface with square sink and single tap and no pictures (or indeed light switches, plug outlets, thermostats or skirting boards). “People came in and were gobsmacked.".