Now that I've simplified your inheritance tree, along with the can_target's, can you see your problem?
Inheritance in order of can_target (as close as possible with current non-splitting branches)
Owner:
inherit_from = superadmin
Co-Owner:
can_target = !%Owner
inherit_from = Head Admin
Head Admin:
can_target = !%Co-Owner
inherit_from = superadmin
superadmin:
inherit_from = admin
admin:
can_target = !%superadmin
inherit_from = operator
Donator:
can_target = !%admin
inherit_from = operator
Donator Type 2:
can_target = !%admin
inherit_from = Donator
Respected Member:
inherit_from = operator
operator:
can_target = !%admin
inherit_from = user
Custom PM:
inherit_from = user
user:
You can't have multiple groups inherit superadmin (or multiple groups inherit the same group) and then set odd can-targets that don't match without knowing exactly how access control lists work, and being confident in how to set them. (Trust me, I can tell you're not quite there, one day perhaps, but not now)
You have Head Admin inheriting superadmin, and you have Owner inheriting superadmin.
I recommend owner inherit co-owner, co-owner inherit head admin, head admin inherit superadmin.
Go from there, see what works/breaks.
(But personally, I'm a firm believer of none of that)
https://forums.ulyssesmod.net/index.php?topic=6291.0