It's a common part of human nature. Assigning bad moral character on the basis of group identity, rather than on individual actions, is the essence of tribalism and bigotry.

Sure, the DoD has an outsized impact on people's lives and a highly controversial history including both major evil and major good.

It seems to me a positive thing that someone of good character and strong capabilities would go to make things better, vs allowing bad actors to accumulate and do what bad actors do.