Ves didn't have much experience with working with light mechs. He considered humanoid medium mechs to be his home ground.
Medium mechs were the most mainstream variety of mechs for good reason. They were mobile enough to avoid getting pinned down by artillery attacks and they were tough enough to provide their pilots with plenty of margin for error.
The load-bearing capacity of medium mechs was also far superior to that of light mechs. Due to their volume, mass and other design properties, medium mechs were able to carry enough weapons and other gear to make it easy for any of them to contribute in battle.
Light mechs traded all of that in to gain more mobility. They were faster, but they paid a lot to secure this advantage.
The relatively thin chest armor of a light mech meant that the mech pilot had to brave a lot of dangers with insufficient protection. This was the biggest reason why most mech pilots would rather not pilot these challenging mechs.