July 2020
I was in Create a Sim, and I decided to put socks on my sim, while they were wearing skintight pants. I saw no socks. I tried with leggings and tights, didn't see those either. I removed the pants, keeping the others (socks or leggings) on, and they finally showed. What's up with that? In real life, you'd be able to have both on, and showing!
August 2020
@DeltaShadowWolf, it is probably just how the socks were coded as the developers most likely just saw socks as items that would be closest to the skin and lay under any pants, regardless of type. And leggings and tights would never be over pants anyway, as that would stretch them out too much! I've never seen anyone wear leggings or tights over pants (no matter how tight those pants were) , either in real life or in the game. (Unless you have Custom Content (CC), in which case that is an issue to take up with whoever created the CC).