Maybe I'm a scrub, but where is the meaty mass of frigates? They can be very effective against anti-cruiser units and the sheer number of them can basically force the enemy to build up their supply of anti-frigate forces.
Frigate swarms are surprisingly deadly without a counter as many of the heavy weapons available can't target them.
It comes down to efficiency. Because Cruisers are more durable, things like healing and regeneration have a greater effect. As well, a Cruiser at 10% health still has 100% of its damage potential; Losing 90% of your Frigates loses 90% of their damage potential.
I don't think it has to do with being a scrub or anything, it's just a different way of looking at the problem. Personally, I also go the Cruiser route, because I prefer to keep individual armies alive as long as possible, and that's just a little easier with Cruisers.