I remember years ago her column where she said, "I may not agree with you but I will defend to the death your right to say it." This young adults are volunteering to do just that and she is begrudging them. I guess she didn't really mean what she said.
Ensuring the prospective recruits understand the risks, and don't see the military as some kind of traveling glamour show is not wrong.
Assuming the kids will balk at joining because of the possible danger is assuming cowardice not in evidence.
This may not be the SAME "Dear Abby" that you read years ago. Several of those old biddies (who were related) wrote the columns America became familiar with but were replaced with other writers as they got old/died.