This is by design and has been like this for a long time. The main shortcut for Zoom is alt + right click drag and this works on both Mac and Win. This alternative shortcut was added on the Mac version to work around the limitation of a trackpad where right click drag is harder to do. Control also has a different meaning on Windows - we use ctrl on Windows to mean the same as cmd on Mac, so ctrl on Mac has no equivalent on Windows. The manual will be updated to make this clearer.