It sounds like you've understood it correctly. The data strongly suggests that COVID-19 isn't a deadly disease for otherwise healthy people, and any apparently healthy young people who die from it are most likely "errors and odd cases". (Although framing it that way could imply too strong of a conclusion - comorbidities in the study include hypertension and diabetes, which aren't exactly rare.)
The hospitalization rates for younger people in Italy and NYC don’t paint such a rosy picture though. While deaths are rare, it’s still a very nasty disease for many younger people, and we don’t have much data yet on potential long term effects.
No, we don't, but what people are interested in here is the lockdowns and when they can end - totally or partly.
The hospitalisations of young people all so far appear to be exceptional cases. This is also true of the reports of "fully healthy people". So far every case I'm aware of like that has turned out to be a lie. It implies the lockdowns could be restricted to the elderly and the frail.
In one case in the UK a woman under 40 was admitted to ICU with no pre-existing health conditions. Worrying, right? She'd been taking 8 ibuprofen a day. Ibuprofen suppresses the immune system and 8 per day is a staggeringly high overdose. The maximum dose for an adult is 4 per day so she was killing her immune system completely.
In another case there was a death of a young person in Spain, reported as no pre-existing conditions. After the death he was diagnosed with an unrecognised leukemia.
It's very likely given how extreme the statistical evidence is that basically all such cases have some sort of mitigating factor. Young people who are healthy and not doing stupid things don't seem to die or even get critically ill.
"The hospitalisations of young people all so far appear to be exceptional cases."
This is just wrong. The numbers are changing all the time, but as of a few days ago, 38% of hospitalized coronavirus patients in the US were between 20 and 54.