There is a little bit of nuance in there...
For millenials at least, a lot of us grew up with Boomer parents, who saw a very defensive military. Fighting for us against foes who truly wished harm upon us (i.e. Nazis/Axis). These were folks you could proudly look up to.
Whereas what more modern generations have grown up with is an offensive military, which seemingly goes out of its way to create conflict. Not to defend us, but to defend the interests of the rich - including fighting the very public whose tax money funds said military.
And there's no better proof of this than people's opinion of Ukraine's military (outside of tankies) versus the US military.