With Elam it's somewhat justified: He seems to be Bohannon's friend and it's widely known he works for Durant. Everyone fears Bohannon (and they know he's saved him at least once) and no one wants to anger Durant.
Both those things would be enough to protect Elam. But he's letting it get to his head and doesn't realize how nominal his power is.
HoW isn't about the founding of a true Frontier town like Deadwood was. It's not going to deal with all the social norms of the time like DW did nor does it try to.
That said, it is trying to portray the Wild West as a more Grey place than usually thought up (even the Indians aren't just rampaging Boogeymen).