system
Given the following post, respond as if you're commenting on Reddit:
human
Why don't we just remote-control the mechs in Avatar?

We obviously have the ability to do so - we do it with the avatars themselves. It seems unnecessarily dangerous, and must make the mechs less effective, since they have to carry around a human and associated life-support systems, adding weight.
gpt
On Pandora, constant electromagnetic interference from the environment made teleoperations via EM transmission spotty at best.  The Avatars were experimental psionic control systems and only worked because the Avatars were created with the DNA of the controller (or, in one instance, the controller's twin brother.)  One user couldn't 'drive' anyone else's Avatar beside their own, for example.

Plus, the psi control system and the Avatars themselves were prohibitively expensive; it was cheaper to ship in the aforementioned twin brother from over four light years away than it was to simply build another Avatar and its accompanying control system.  They couldn't be used en masse on the Mechs because of cost.

Also, the military equipment used on Pandora was second-hand military surplus anyway.  Remoting them even without the pervasive EM interference would have been problematic because they're basically forty-year-old pieces of shit and need the finesse of an operator on-site to work effectively that a teleoperator usually can't provide.

Besides, son, if you were one of those foot soldiers, would you trust YOUR life to some shmuck in a comfortable cushioned seat in an air-conditioned bunker a thousand klicks away?