Comment by happosai

If you look at cycling as a purely sport/exercise thing, you are right. But if you look at cycling as a transport method to get from A to B with incidental exercise benefits, it looks different:

Sure if you assume that someone switches from conventional bike to e-bikes and continues to only travel A to B like before, yes it's a net loss in exercise.

In the study however, they found lots of people substituted driving or public transport with e-bikes, which is a net gain from the reference point.

Even for people who had conventional bikes, getting a e-bikes meant travelling with e-bike more often and longer distances than with a conventional bike.