Why is almost everyone on the attack list not available to be attacked?
Ans: Because they are in damage protection ; damage protection is given when
1) If you loose 40% or more of your fleet in an attack on your empire
2) If you loose 3 or more colonies in an attack on your empire
how do i retaliate against an attacker??
Ans: You have 7 Days after the attack to retaliate against an attacker, just perform a normal attack the next time you see him out of damage protection