I think part of it is because Killer is so active here and does eventually share the game himself when it goes public. I think any Dev that actively engages here and freely shares his/her game deserves the respect of not sharing "paid" posts even if they don't seem to mind. If they want to share it, that's up to them. At the risk of speaking out of turn, Killer might not react negatively, but I don't think he likes or appreciates it.
As I said I'm a hypocrite and my opinion is totally different with a dev like DS who does Glamour/BB, he has no interest in participating here and a lot of what happens we would no know without people sharing paid posts. I also won't normally support a dev without knowing more, and I don't support any without first asking them questions about planned content. So unless they are active here and I can ask directly, the only way is if someone leaks posts.