It could be a legit symptom. Missed buttons, clothes on backwards, mismatched shoes or socks, a dress with pants - all of that could indicate deeper issues where your brain is slipping gears. It’s a real symptom, and I think those exact words appear in the DSM

Or this doctor was just a judgemental asshole who has no idea what self expression is. The entire profession is based around pretending to know what’s going on, a lot of them are shockingly incompetent when you get past the jargon