Thoughts on the first question:
“Vice” implies a character flaw, and since wars of any kind typically increase sales and profits for defense contractors, the argument can be made that profits come at the price of lives. Trading lives for shareholder dollars can reasonably be thought of as a character flaw.
Even defensive technologies, such as armor, can be rationalized as ways to kill opponents more efficiently. Some might also make the argument that you’re just determining who is killed - us or them - but not changing the sum total. (not saying I subscribe to this rationalization, but the argument can be made)
And defense contractors typically do not distinguish between wars of “defense” and wars of aggression. They make money either way and are unlikely to say “Sorry Congress, we don’t believe this is a defensive action, so we’re sitting this one out and not shipping you anything.” Furthermore, defense contractors can be opportunists and choose to sell to countries abroad not interested in “defense.”
Finally, no military provider ever categorizes itself as an “offense” contractor. So the term “defense” is really just an industry nicety.
I’m sure other folks will be along with cites that a lot of “defense” contractors instigated or at least cheered for arms races, especially in the early 20th century and with the Military Industrial Complex (my cite here is also that it’s also a world wonder in Civilization Revolution. I conquer all in the name of defense!! :))