That’s what people will tell you. And in some places it might be true. The trouble is that a flat country next to the sea will also tend to be windy:
Give me hills instead of a headwind any day – at least with hills, you get a respite as you ride down the other side. A headwind in comparison is relentless, AND (in strict accordance with Sod’s Law) the wind will change direction just in time for your ride home.
So what is it about the Netherlands with its networks of safe, convenient, prioritised, segregated routes, makes so many people prefer riding a bike to driving?