As a parent, Discord is the number 1 threat to my children. I gave them the whole "stranger danger" talk, and I regularly check in to see if anyone is harassing them. My kids are honest and my 14 year old has gotten multiple people asking for inappropriate photos in one of the Fortnite server (not sure if it's an official one?).
I don't want to ostracize them, since they use it for playing games with their friends in private servers. Actually another parent I know specifically admins his own kids server and only lets them communicate with their friends via that server.