Blockland glass is non-profit. I'm a record producer in the music industry so I've studied the law of it. Since it's non profit, the original author(s) of the work(s) won't have any losses as a result of the thing not making profits, or money at all. Also if it's less than a minute of music it usually is fine.
Blockland Glass Hosting is making profit though, so is that still not under the law, if not the case then maybe Blockland Glass should host music then, I think it's still worth a shot
Who cares about copyright though? All you have to do to is remove specific files that you get a dmca complaint for, and make people check a box "I am the owner or have permission to upload this content" when they post an add-on. Then the blame is no longer on you.
Is there a time limit to respond to them