Why are index finger trigger releases considered unsuitable for compound target archery?

Question

but thumb triggers are okay. why?

Answer 1

I've seen those at tournaments.  But the downside to that is the urge to punch the release.  This is when you anticipate the shot and jerk the trigger.  When you jerk your index finger, your entire hand can come forward and make you miss the shot.  Jerk the thumb and your hand won't move much if any at all.  

Another type of release used by compound target shooters are the BT release, or Back Tension release.  Where the release is done by squeezing the back muscles, much like recurve archers do.  While most pro shooters train with them, usually they still prefer to use the thumb release for actual competition.  They want the ability to punch the release when it's suitable to them and not be dictated by their backs.

Answer 2

Some still use them in tournaments, but most of the top pros use the back tension releases. the main complaint of the index finger releases, is that there is a tendency to punch the trigger instead of slowly squeezing it until it goes off- when you punch the trigger, there is a movement that throws off your aim just a tad- while this is not a major factor in hunting, it can mean the difference between first place in a tournament and perhaps fifth place, or even last place.

Answer 3

It's a mechanical device.