Earlier quoted context omitted.
If they've been writing for decades they aren't 'hot new writers' over 70.
The emphasis is not on the "new" but on the "hot new". You can hone your skills for decades, and even publish, but only become "hot" (based on some nicely selling or award winning work) later in life. You still deserve to be in a list.
I think this is pedantic, but whatever. If you include previously popular authors then your article is not look at these new authors who are seventy, its look how old these authors are.
Or at least, that would be my takeaway if number one on the list were Steven King. It’s not interesting that he is still a good author. It is noteworthy that he is older than I expect. He is ~72 btw.