The app is great, no ads, easy to add your friends, etc.
The thing that bothers me the most, is how parents think there is so much NSFW. Its going to be your child's or your fault for letting themselves/the parents get through to that group.
Discord is a widely used platform, and it's quite frankly not possible to constantly go through hundreds of messages in several channels from one server at a time.
Blocking a person and/or simply denying their friend requests are simple ways of handling this straight off the bat, and let's not get into the settings that you can put on your account to prevent people you don't have added, don't share a server with, etc, from messaging you.
Leading on from this, Discord does have a setting that will automatically block what you don't want to see- mostly NSFW things that I imagine many parents don't want their children being exposed to.
It allows people to chat and screen share very easily.
The problem I have is that they are pushing themselves as a platform for gamers, frequently children, but they do not limit the platform to gamers. If they want to have adult material, they are supposed to tag their channel with "NSFW".
There is no way to prevent a child from going back into the settings & flipping that button back to re-enable explicit content.
When I contacted Discord Support, they confirmed that there is no way to password protect those settings.
However, as stated in Discords rules/terms of conditions, server owners are required to have a set channel for NSFW content that requires you to confirm your 18 and safe to view.
In that retrospect, your child made that decision to view that content, and is not at the fault of the server owner or Discord itself, because quoting Teamspeak- "This is Teamspeak, not Spyspeak".
I know you may want to think that your child is sweet and innocent and weren't put up to it voluntarily, but that's quite frankly not true from someone whose been using the app for over a year now.
I know it inside out unlike many of the reviews here, and I hope that this clears a few things up.
They have a "Parent's Guide to Discord" which explains how to set up your account so that it will block explicit content or block certain people from contacting you or friending you.