Because their first use knew what road it would lead them down.
The vast majority of people aren't starting with heroin or fent. They start with getting prescribed cough syrup with codeine in it, or a friend offers them something 'fun' at a party. People aren't making a single decision like, "yeah today I'm gonna ruin my life."
And what about them? You can feel bad about them and bad about a celebrity dying. They're not mutually exclusive.
It's harsh to phrase it this way, but frankly I don't care all that much about the One Direction guy that died personally. I wasn't a fan. It didn't impact me emotionally, but I can still acknowledge that he was greatly loved and it sucks for his fans and- I assume- his family.
Terraria is one of my favorite games ever! I've been playing it on and off since 2011.
In case you missed them, the guide has some extremely helpful dialogue options. At least on PC. I can't imagine they'd leave that out of the Xbox version.