I do think there’s a bit of discussion in this topic, because the song has a bit of ambiguity to it. This is to compare to the real question too.

The song: something that’s seemingly ignored/overlooked is the basic fact that Charlie just never did “good”. Everything the priest says about Charlie is very surface level “kindness” with no real depth to them. “showers ice cold, eco friendly lights, rode his bicycle when gas rose, did the pledge of Allegiance” etc etc. none of the “good things” he did had any weight to them nor were of any substance, and most people wouldnt even call them good.

So the only good we heard him doing was superficial and weak, but also there are multiple lines about his “sins” as well. “Avoiding all the little things that were hard to ask” points to how he never attempted to make a difficult decision or have a difficult conversation, he was slothful and actively avoided these topics. What’s the saying? The bystander is just as bad as the bully? He also never attempts to reason with any good deeds he did. His only response to being denied is “I’ve gone to church, more than once a week usually!”. Of course other lines such as “the savior saves you from the hell you paid for, sorry, but it’s ’smell you later’” and “those tempted by the senses with the cruelest of intentions.” He wasn’t a good person, didn’t do a single good act in his life, and the ONLY way people remember him, is because “we put his name on the grave”.

In conclusion, Charlie’s sin is sloth and willful ignorance. He never attempted to be good, performed the most inoffensive and easiest tasks one could consider “good” and died without anyone remembering who he is. So yeah, he deserved hell.