No offence mate but how can it be impossible to select gears in neutral. How are you supposed to drive? Or am I missing the point 
With the clutch not fully depressing, it means the synchro rings have a lot of load on them, which increases the shift effort. It'll also shag the blocker ring fair quickly too.
To take it to extremes, it's like trying to shift without depressing the clutch at all. You can do it when the car is moving (if you manually match the revs and road speed), but you can't do it when the car is stationary.