Yes socks that we wear on our feet are considered to be clothing.
But also socks are considered to be accessories as well.
So some people only consider socks to be clothing while other people consider them accessories.
The socks are clothing because they are covering our body and they can also be accessories.
Some things that are considered accessories to our other clothing are things that include jackets, boots and shoes, cravats, ties, hats, bonnets, belts and suspenders, gloves, muffs, necklaces, bracelets, watches, sashes, shawls, scarves, lanyards, pins, piercings, rings, and stockings and yes the socks.
Socks help protect our feet and keep our feet warm.
The shoes do the main protecting of our feet but the socks protect the feet as well and make it more comfortable to wear the shoes.