the money is there to store wealth so that it may be used to buy things. when something to be bought is more desirable than holding on to the money for later, a person uses the money to buy things. the breaking and replacement of the window forces less-desired purchases than if it had not broken. yes, this results in economic activity, but there would have been economic activity from the other things that the money would have been spent on, which do not involve the destruction of wealth. the jobs associated with fixing broken windows are important in an economy where windows break sometimes, but the entire endeavor is less desirable than an economy where fixing that problem is unnecessary, and those people do other things. imagine if humans suddenly acquired permanent perfect health. the health care industry would collapse, disrupting a lot of the economy. but everyone would be better off, and the resources now spent on health care would instead be spent on other things. gdp is, again, not the only measure of importance, and a policy that sacrifices wealth to promote gdp is bad.
United States