Even though I like the campaign, I really do agree that the xenomorph shouldn't be infected by the pathogen, it's in the bloodstream in some extent. It just feels weird that they can get infected by this, they are said to be perfect organism and they're getting their asses Beaten by a zombie version of xenomorph, I don't like it. And yeah isolating the crusher into that it came from a creature with thick skin, also bugs me. At least it been recon in the dark descent.
One more thing. This is unrelated but I was listening to the Seegson Lore, The last sentence really intrigued me.
"I've heard in the 70s they try to colonize some planets in the middle room, wonder what happened with that"
Imagine the storyline like that. Seegson try to colonize a planet but The columns has been attacked by xenomorphs that were from a abandoned Weyland Yutani colony on the same planet