There are ways to make useful your frigates and even keep them alive. I tend to use them as anti-fighter support, EMP missile SPAM and defensive platforms. EMP SPAM is one of the best uses for frigates, since you can knock out everything while cruisers blow up everything. That combined with FORMATION order to keep them behind my cruisers, and some frigates with anti-fighter weapons (to keep those little guys away, cuz they like to kill your frigates) works fine for me, most of the time xD
You can control this (to an extent) by careful management of your engagement distance. Once a ship has picked its target, it will move to the specified engagement distance away from that target. It will move was needed to keep the distance between the engagement distance and half that value. (If you use Keep Moving, the ship will do its best to wander in that ring-shaped band of space.)
Of course, this is not guaranteed, since the ship’s driving AI may move it well into range of enemies other than its chosen target. But it can help keep your frigates away from the enemy’s nastier (close-range) weapons for a little while at least.