Changed your thoroughly offensive title.
And yeah, as people have mentioned, walking distances need to take map obstacles into consideration.
The walking distances for bottom are considerably shoter. Moreover, due to the higher density it is much much easier to support an attacked sector from another. Finally, mortars, snipers and HMGs have much better coverage, if you make use of the gratiously provided houses there.
I don't see how anyone can think that the hedges actually change that.
Statistics are also available: I have lost exactly zero game starting bottom and lost all games starting top. I am actually just quitting this map everytime I start top now.
Definetly not true, i just swept my opponent off the face of the map , was top and didnt had problems, map doesnt win the game nor the units on them selfes (thou both can contribute they are not the deciding factor)
If you have swept him off the map that is a good indicator that he wasn't very good at whatever he was doing. If you are actually in a tight match, defending as top is a nightmare because the enormeous walking distances between and to the sectors are a nightmare. If you attack into bottom he can quickly switch over some unit that is capping left/or right to support the defence.
Finally, top really has to just to care about the left side of the map wheras top has to be omnipresent.