Who can tell? The WSJ article doesn't even say whether TP-Link hardware or software is the problem, which would seem to me to be extraordinarily important in reporting on this issue.
To be a little more charitable, I don’t think the average non-technical newspaper reader knows or cares about the difference.
Most non-tech people I know treat a router as a black box system - you plug it in, and then when you have issues, you turn it on and off again. If it keeps happening you get a new one. The word firmware will draw blank stares.