Im somewhat confused as to why defense is worded the way it is. Obviously it is meant as Rules as Written and i understand that, however..

If multiple sources of of defense do not stack, why would anyone wearing armor granting even ONE defense value ever use something like Guarded Stance maneuver, take advantage of the defensive property on weapons/armor, or use cover? Sure each one of these things has situational modifiers as well(All of which stack) which make them beneficial, but why would defensive bonus's from different sources stack? If i'm wearing Armored Clothing(Defense 1, Soak 1), wielding(or dual wielding) Vibroswords(Defensive 1), and using the Guarded Stance Maneuver(Defense 1, amongst other benefits).. to me thats all very different things that make you more defensive in melee specifically. Add in cover and you add in another +1 defense score vs ranged attacks.

Does this not make sense?

The difference is how those talents/qualities/etc that increase defense are worded.

Armor and Cover are both "provides appropriate Defense X". They are flat numbers, and thus don't stack.

However, something like Defensive or Deflection, both of which say "increases appropriate Defense by +X" do combine with Armor or Cover.

So for the example you gave, you'd get Melee Defense 3, as the Defense from the armor (base 1) combines with the Defensive quality (increases by one) and the guarded stance (increases by one).