This rather asenine question is presumably intended as a provocation to people who want to reduce the horrific murder rates in the USA by introducing gun control. The answer which best meets the question at the level at which it is asked is: if there is no gun then its trigger will for sure not get pulled however unstable or wicked the person who has the non gun in his hand.
Yadayada then answers his/her own question rhetorically: . . . . If you can figure out way to stop people from killing you wont need gun control.
Hmmm. Well you won't ever stop people from killing of course. Even with gun control. But gun control will make it considerably more difficult to kill. So common sense dictates that if you want to reduce murder rates then introduce gun control. However stopping killing isn't everybody's priority. For some the right to own a gun comes before all else whatever the cost. But if you could stop people killing then of course gun control would happen by itself since nobody would be interested in having one. After all, barring suicide, there isn't much else you can use a gun for other than to kill or wound people.
Which brings up an even more interesting question: do guns control their own availability? The answer might be: If you could find a way to make them unavailable then people would no longer feel the need to defend their right to have them.
A trigger is a Mechanism that uses other Mechanical parts like a chain reaction to allow an action to happen (ie - the Bullet to be shot)
for a mechanical part to move against pressure on its own is impossible unless there is more force put then the pressure behind the trigger.