Some would despise
Einstein for that, claiming that without the conviction to back his beliefs with personal risk, his teachings are corrupt and worthless.
The complete and real question is not 'is war bad' or even 'is preparing for war bad' but 'does the term bad apply to war?' Think about it. 'Good' and 'Bad' are terms assigned things by humans (yes, I'm consciously denying Objective Moralism or whatever that abortion of a philosophy Ayn Rand was spouting). They are not qualities assigned by the universe, with convenient labels. Einstein's words, interpreted from a different point of view, might be interpreted as crass cowardice.
I for one am rather unhappy with this constant attempt to belittle the United States' efforts to protect and preserve itself through specious comparison with the budgets for science and technology, entitlements, etc. Think of this another way: Entitlements take up (by far) the lion's share of the Federal Budget. What are these entitlements? Besides the perhaps defensible plan of caring for those invalided, billons of these dollars go to fatten the retirement coffers of a) people who did repair for retirement and thus don't need it and b) people who could have but didn't, and thus don't truly deserve it. They had forty-odd years to make plans.
Back to preparations for war. These sort of bleeding-heart nitpickings over the budget are almost inevitably followed with passionate discussion of how the violence these monies fund is bad, wrong, horrible, our fault, etc. I have some news. The lion's share of the defense budget (not the whole budget, the defense part) goes not to toys, and not to foreign militaries (that's Foreign Military Aid, a different budget) but to Americans. Americans who serve in the armed forces. Americans who work for corporations who make goods and services for the defense department and the government, as well as for those governments eager to spend that $850 million we just gave them as 'aid'.
The line of reason from 'X dollars spent on defense' through 'Y < X dollars spent on research and pure science' on to 'Z violence is done with our money', while interesting, makes no coherent sense. What they do with those military purchases may not be what we intended, but what right have we to interfere in their internal policies? No more than they have to interfere with ours. If you claim that we have a right to based on our gift and the relative power of our nation, then you're no better than they! You've just acknowledged that power decides, in which case violence isn't 'good' or 'bad', it's simply a calculus of power. That's necessary if there are to be interactions that don't involve tests of strength; there needs to be common evaluation of the balance/difference for there to be peace, and sometimes that can only be attained through violence.