Case in point: I was in a Matrix room. Someone came in and started posting extremely gross images. I left that room and have not returned. In that case, the client I used lacks filtering & blocking options, so other than closing the client until enough time had passed to attract administrators to kill the offending account, leaving the room entirely was my only option. 

If leaving the room had not been an option, I would have deleted my account and the client software. 

 All the NSFW content I've seen on nostr has content warnings, so nothing is displayed unless you explicitly click the show button. 

 You've been lucky, then. Not everyone tags / CWs such contents.

But this is mostly a subpost of a conversation in another thread where someone was angered about a client that filtered some post from its 'trending' list. 

If we want to see numeric growth in the network, some client will have to become "normal person friendly" and default to filtering. It won't have to be on by default in all clients. Just one or two that people new to Nostr can start out using.