Difference between 'casualty' and 'victim'
Solution 1:
One of the differences is that victim is a role, ie how we are viewed by ourself or others. Compare these alternatives:
2a. I won't allow myself to become another casualty of these people.
I won't allow myself to be hurt by them.
2b. I won't allow myself to become another victim of these people.
I won't allow myself to be hurt by them AND/OR I don't want to think of myself as being a victim, ie to take on the victim role in my relationship with them.
"Casualty" doesn't have this connotation.
I think that in your first example you could use "victim" without changing the meaning.