The red icon on Tie Bombers isn't the 'Bomber' ability.
It appears that the Bombers have the same ability like Luke has.
I think the red icon is some sort of an 'Escape'-Rule. Maybe you have to take a roll that determines wether your squadron takes a hit when using the ability.
So, I think even Bombers need to get into range 1 of capital ships in order to attack them,
unless there will be some sort of upgrade cards for Bomber squadrons available.
Source on this information? Did you play the demo?