I have a major problem with this story setup. How in the hell could the ISA allow the Helgans to run free on that side of the wall. Give the survivors sanctuary sure but free reign to build up an entire counter civilization!? Also why are there so man of them anyway?
See, you're not looking at this from a realistic point of view. You're basically saying they should be treated as animals with restricted rights and should only be allowed to "survive".
In a realistic scenario the people of Helghan are the real victims, of a brutal mass murder and destruction of their home planet. After the fact, they still are being caged in an apartheid scenario against their will. As they see it, they have rights, to defend themselves from this oppression.
"Why are there so many of them anyway?"
I don't know how to answer that, other than ISA are not the ones to decide whether or not the helghast are going to reproduce in order to save their race. Remember, the ones left on Vekta are the only ones who survived the attack.
If you read up on the entire storyline on their homepage, you'll soon realize who the true victims are.
I want nothing more than a Killzone game from their perspective, both through the storyline and gameplay... i'm sick of the ISA and their oppression, i just wanna kill some ISA soldiers.