Heh, it's ok. Journalists make LOTS of mistakes.

Yes, the prior ATV4k supported ARC (how do you think all of us have been using the Sonos Arc currently?
For the most part, only newer TV's with HDMI 2.1 ports will have eARC support - but a lot of the manufacturers have been playing "fast and loose" with compliance to the HDMI specs. You could have HDMI 2.0 ports with eARC support and HDMI 2.1 ports WITHOUT eARC support (which, obviously, should NOT happen).

People need to be careful and confirm what their TVs support when making their purchases. (it shouldn't be that complicated...)