My interpretation was that Simone punching Grey was for not confiding his feelings with her and "running away from his problems", rather than confronting them(by telling someone). As far as Simone knew, Grey's note was the first time she had ever heard of his suicidal feelings and it was to tell her and Et he was going to k*ll himself. That being said, I understand if that reasoning doesn't make it justified in someone's eyes, and it makes them uncomfortable, but I see it as a realistic, flawed reaction if nothing else. You have to remember that Burrows is a story about flawed people who don't always make the best decisions(our boi Grey is a canonical cheater for crying out loud!)
As for joking about suicide, I don't know if you have personal experience but a lot of people with that mindset use dark humor to cope/process and it's not necessarily indicative on Nikkos's feeling on the seriousness on the subject of suicide.
Sorry, I know you wanted a response from Nikko, I just saw your comment and thought I would share my perspective on the questions you raised
