This is a very naive and untrue statement.
Many of these troops are from areas where there is little or no opportunity.
Rather then joining up because they want to kill people they join up because it is a chance to learn a trade, gain qualifications and gain opportunities that are not available otherwise.
The Welsh valleys for instance are over represented in Infantry Regiments for these very reasons.
And they know full well that part of the job is killing people. I'm like the weather me, I take absolutely no notice of criticism.