I could be working 23 hours a day and dh could be at home all day and his only job could be laundry, I would have enough respect for him to put my own dirty underwear in the laundry basket instead of telling him he shouldn't have a problem picking my used underwear up for me.
Its rank and disrespectful regardless of how many hours he works. Even if you've agreed to do all the housework, or if you've agreed to do the bare minimum, he doesn't get to tell you that he can drop his dirty underwear where he wants to and you have to be ok picking it up for him.
Women telling their husbands they shouldn't have a problem picking up their dirty knickers up all the time because he's at home more are just as disrespectful.
I can't imagine deliberately leaving dirty underwear about for anyone to pick up, can understand an odd time in a rus, in which case you'd apologise. To turn round and more or less say you shouldn't complain and be happy to pick his dirty underwear up for him shows disrespect in my opinion.
Dh would leave his in bathrooom floor when we first got together, not just pants, his whole work clothes, they'd be ok the floor touching the laundry basket ffs, I had a rule if it's not the ok the laundry basket, I'm not washing it. He just washed the stuff himself when he needed it doing and realised talking an extra three seconds to put in basket like everyone else in house saved him rushing about on a Sunday evening washing work clothes.