Guys, look at the list. Those are all (relatively) close range weapons compared to bombs or rockets. Most bombs and other explosive devices tend to have a pretty high rate of collateral damage as well. Bigger the bomb, bigger the problem.

In that sense, the A-bomb (or any other similar device) is really not that great. Gas attack would at least not destroy the infrastructure/physical value of the area in question.

Use of any weapon is an act of desperation, not limited to any particular type.
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"In case you ever wondered what it's like to be knocked out, it's like waking up from a nightmare only to discover it wasn't a dream." -Forrest Griffin