It's similar to the discussion around flying. As an individual, me not choosing to take a flight doesn't change much. That flight is still going ahead. It's the same with data transfer and network energy use. Me sending a few less kilobytes over the network isn't going to signal to the network operator that capacity can be reduced. Like flying, though, we can collectively signal to airline operators that certain routes are less valuable if a sufficiently large number of people stop flying them. But that's a long game, with a lot of collective action required. We can get there, especially in places with suitable alternatives to flying, but we can't completely remove flying from our life. I'd say the same applies for the network. It's not a lost cause, but rather a long game that we can play alongside realising shorter term wins.
When I read this, I had a hard time because I do understand the argument, from the POV of there being an airline route in the first place, the current framing focusses so much on an indivdual case that you can miss that on the scale of hundreds of people, doubling the people flying will very likely double the emissions.
This is because the key driver of emissions is burning the fuel, and because airlines scaling up and down the frequency of flights happens on a much faster frequency than laying new cable and network infra.