So by this logic, e bikers eat less on days that they ride? I doubt there is any data to back this
It's probably that they don't need to eat as much as the equivalent person of similar stature, age etc who is riding a non-ebike the same distance. If I'm burning 400 calories riding a normal bike to ride 20 miles, and an ebiker is burning 200 - I need to consume those additional 200 calories somehow - and that has an impact on the environment too.
In some ways, it should be self evident that electric powered transport could in some circumstances be more carbon efficient that human powered. One would never attempt to power our home lighting and appliances through human power alone when there are perfectly good and low carbon sources of electricity. which are more efficient that humans at generating electricity. Ebikes might, according to current data, also meet that sweet spot on the transportation front. Add in other scenarios eg the ebike displacing car journeys because people no longer arrive at the office hot and sweaty, or are able to transport their shopping home when they'd previously take the car.
For me, I use both ebikes and normal bikes so am not ideologically wedded either way. Ebikes I use for commuting, shopping etc as being in my 50s, having a physically demanding job, living in a hilly area with regular bad weather and a chronic health condition meant something had to give. It was an ebike or getting a car or stopping work as public transport provision is appalling around here. For recreation and enhanced fitness, I use a normal bike. If my health further deteriorated, I would happily join my ebiking friend who has only one lung and use an ebike for recreation too.
What we do need to do is make sure ebikes fit into the circular economy, and are ideally as robust, modular and easy to fix as normal bikes. My first ebike packed up after 4 years, and approx 10,000 miles. Not bad for a £350 bike. It required very little other maintenance as its a single speed. It is possibly fixable, but unlike a normal bike I do not know how. It's still rideable as a normal bike and likely if I give it away, someone will figure out how to fix it. My current ebikes, one a conversion/one not are built with more standard parts which should mean I can keep them running longer.