Why attack-move order can't be done with left mouse click?

Hey
does anyone knows why all the order like reclaim, move, patrol, repair etc. can be used click the specify hotkey + the mouse LEFT button but the attack-move order have to be used with the specified hotkey + the mouse RIGHT button ? Is there a particular purpouse for this? I find it annoying because when you attack move engies inside a reclaim field the order will probably taken as reclaim

thx in advance fellas!

Wasn't there an attack and also a attack move?
Here are some facts:

1. 95%+ people use alt + right click for attack move
2. There are two attack modes. regular one and groundfire one...
   Difference between them is that you can't groudfire in regular mode.. but also in groundfire mode clicking attack results in attacking ground. in regular mode attacknig ground results in attack move...
   As far as i remember devs someday decided to make groundfire mode to be default, cause they just never know that someone uses left click for attck-move.

So before that change there were many people using UI mod that puts units in groundfire mod by default.
Now if you want to attack move with left click you need to put your units in regular mode, instead of groundifre mode... i think there must be a UI mod that can do that for you automaticly.... i think "UI Party" can do that but not sure

hey Zlo, thanks for sharing the facts, most of them I didn't even know about.. but what I would like is to use the left click for ENGIES, and they don't have the regular mode, just the ground fire one, and they can't switch it.

In few words I would like to make the attack-move the same as reclaim, patrol, move etc. functions, i.e. that when clicking Alt your cursor become of the attack-move instantaneously and you can use the left click. This also because when your cursor is above a reclaim field if you are zoom in close it becomes of the reclaim type and if you click Alt it won't change. But I think this can't be done without some new UI mod..