Americans have been conditioned to think our troop interventions are defacto always in self defense, never as aggressors, and that supporting US policy equals supporting the country---thus NOT supporting the troops equals not supporting America, or even supporting the enemy. In some countries like Turkey, criticizing the troops is considered a crime.
It's important to remember that prior to the '70's, American evangelicals were mostly uninvolved in politics at all, until the major media began its infowar to normalize fornication and later homosexuality, while the Supreme Court effectively banned school prayer, legalized porn, and decided all the different state laws restricting abortion were somehow all equally unconstitutional.
The social right upheaval was, and is a response to the social left authoritarianism and propagandizing imposed on this country via their control of the courts and the media, regardless of some coercive counter-policies the right has at times suggested as a solution. As Lawrence Vance and others have documented on LRC, many evangelical strains in American history have been flatly anti-war, or at least neutral as it bears on foreign policy.