It's not unfair to state that this disease, is much, much more dangerous for the 65+ age group. That being said I don't agree with the grandparent OP.
So, out of the 54 people under 40 that died (~0.25%), 38 had significant other issues. And only 10 (~0.05%) were otherwise healthy people.
I’m tempted to agree with OP that it seems like it’s more of a bad flu for younger people.
Of course, it would be interesting to know how many of those younger people actually needed medical intervention to save their lives. Maybe the death rate amongst older people is so much higher because doctors prefer to treat/save those that have a chance when hospitals are overwhelmed.
In another post I described how I’m tracking a cohort here in the US of healthy young MDs who are experiencing symptoms consistent with lung injury +42 days after symptom clearance.
A bad flu does not limit you from athletics for life. COVID might. We just don’t know.
The point of the article we are discussing here is that with COVID-19 this is not a binary live/die situation. You can live but still have serious lasting lung damage, possibly lasting neurological problems as well. I'm not aware of the flu having similar effects after recovery.
I did find multiple references to 20-30% reduced lung capacity.