I don't want to get into an argument and you are certainly entitled to your own opinion, but the military is a pretty old profession and has dealt with this pro

I don't want to get into an argument and you are certainly entitled to your own opinion, but the military is a pretty old profession and has dealt with this problem before. JTACs are basically radio/telephone operators, and often aren't physically with the unit calling in the fires because there are more platoons than there are JTACs, so the JTAC sits at the company (or sometimes up to the brigade) HQ and handles a whole bunch of platoons at once. He takes what the ground commander says (via radio in the field), and passes that to a control center via telephone, IRC (seriously), satcom, etc. The control center then routes a plane overhead and facilitates direct contact between the pilot and JTAC (not the ground commander). The real specialty of the JTAC is speaking in both Air Force-isms and Army-isms and communicating clearly with both parties. Imagine a weird game of telephone where adding another person in the chain actually makes the message come out more clearly at the end. So to wrap up a long story, there's a whole lot of communication being passed around and it would be awfully difficult for a JTAC to just decide "I'm going to get that family over there killed because I feel like it"