To be faaaaaair, with so little feedback and communication from the devs. You can only make assumptions as to whats intended or not. For all you know the devs are aware of these “exploits” and consider them fair game or not worth fixing.
For all know, the devs intended for an alien discharge to pass through primitive human structures. For all we know the devs never wanted Preds to be defenseless and locked in an animation after a slam, and do infact want them to move freely after slamming. Knives being strong enough to take on a predator, could also be a exploit. Being able to main hand your knife so you can run faster and deal high damage, also could be an exploit.
Assumptions can work both ways until devs have the final say. And till they communicate with us, no player is in the wrong. As sad as that may be.