They're adults who have a job that requires them to dress in long trousers perhaps?
An acquaintance of mine once pulled me up for wearing what i'd describe as smart shorts. They weren't the casual bordering on scruffy objects we see on certain types,when the sun comes out and they grab the nearest pair they can find. No,these were/are pleated and had/have turn ups on.
. Anyway,he asked me if i wore them when out socialising. Yes of course,seeing as i don't wear anything but shorts from April to late September at the earliest,i replied. He said that if he owned a restaurant or a pub he wouldn't allow me or other shorts wearers in as no matter how tidy the shorts are,as Englishmen shouldn't be seen in shorts,unless they're by the pool on holiday. I pointed out such examples as Sir Roger Bannister running the 4 mInute mile in shorts and the soldiers in the 8th Army wearing them during WW2. Even then he said they should've had their legs covered up. Maybe this had something to do with him having short fat pasty white legs,which he told me he had. I asked for proof. He rolled up his trouser leg and low and behold he had such things.