To sum up, fighters like the Kulas were designed to be cheap, expendable, very easily mass-produceable fighters to get more guns in space shooting at bombs, bombers and beam emitters. A perfectly logical way to counter the numerous but slow Shivan bombers and their numerous but weak fighter escort. That strategy is absolutely inadequate against the advanced and trained fighter corps of the UEF, and the sheer amount of anti-fighter firepower their capital ships can deploy. Wave 2 fighters were (more or less hastily) redesigned with that in mind, but they were originally, much like wave 1, designed with Shivan fighters and bombers in mind. Wave 2 fighters were kind of supposed to be to Wave 1 what the Seth or the Horus were to the Anubis.
For example, the Atalanta was (at least that's what I deduce from the tech description) originally supposed to be the interceptor class the Tevs have lacked of since the decommissioning of the Valk, a ship fast enough to close the distance with incoming bombers, and with enough firepower to kill them fast. It was then modified so it could be agile enough to deal with UEF fighters, making it more like a Perseus MkII (it is ironical that both the Perseus and the Atalanta were designed as interceptors but ended up in the space superiority role).