system
Given the following post, respond as if you're commenting on Reddit:
human
[Grimm] Why do most Wesen act surprised to learn that Nick alongside being a grimm is also a detective?

Granted to the best of my recollection this only seemed to be a thing in the early seasons but the Wesen usually acted surprised or confused to learn that Nick was a detective. 

My question is why? It seems almost everyone in the Wesen and Grimm are capable of having normal day jobs or be public figures living ordinary lives. In fact one of the resistance leaders who acts confused upon finding out that Nick is a cop is journalist well known enough that Nick already knew of him. So if everyone else is capable of being a part of society despite who they are why does everyone seem surprised that a Grimm is able to as well?

Granted i've only now just started rewatching this series for the first time since 2017 - 2018 so it's possible they explain this later and I just forgot.
gpt
It's only referenced but never fully explained in the series. Most Grimms are members of the royals personal militaries. They don't have day jobs they just hunt monsters full time. At least a handful being the Burkhardts and Trouble's family seem to be freelance outsiders. Nick's family never worked fully for the royals and mostly did nomadic wesen hunting when unexplained murders happened. The idea that a librarian could moonlight as a monster slayer is just incredulous among the wesen community. Nick being a detective is likewise bizarre to them. For the wesen it's like hearing that a hitman works as a bellhop in between contracts. Or that the grim reaper needs to pay bills.