No, no one sane would advocate for another WWII.

However, a nation that implodes is also incredibly unpleasant. The most well-known is going from Rome to the Dark Ages. This path should also be avoided.

Re: resource scarcity, it's counter-mainstream but I'm not sure that's correct... net actionable resources might even be increasing - see, ex, all the energy that can now be gotten out of thorium. If you're a believer in cold fusion being possible (hot fusion already is possible, but isn't economical) then fossil fuels are basically a non-issue. But that's a long conversation. Suffice to say, I think the Earth can prosperously contain many more people than today, and that if it did so, it would be more prosperous. Much moreso, actually, since all gain comes from talented people and groups doing interesting things. But that's a long conversation.

Anyways. My argument is "completely pacifist societies seem to self-destruct" - there are a few rare exceptions that are extremely mountainous or islands or mountainous islands. Even they have some defense forces. But yes, I think a small amount of militarization goes a long ways towards having a more healthy nation that isn't self-destructing, which is important.