The majority of people serving in the US military are middle class white people though?
This. We can talk all day about edge-case exceptions who really do have a good reason but the fact of the matter is that the military is populated by the privileged.
here's a citation for the factual inaccuracy presented there: https://www.cfr.org/backgrounder/demographics-us-military
racial minorities are slightly over represented among the enlisted in total, but they are definitely far from the majority, and statistically less likely to be among the poorest.
that said, we should try not to vilify individual service members without specific cause (i.e. that particular person saying reactionary shit), just as a matter of practicality. we have enough enemies as is.
The logic is solid, actually really solid, people react and adapt to their material conditions, and that's why we need to be around those people and build with them an alternative, another solution, that won't just be the one for their kid, but will help every other kid in every other precarious circumstances, that will build and better future for all. But given the conditions I don't blame people on her condition at all.
I don't know about "for a reason" but when I was in most of my fellow enlisted seemed like they didn't plan out their paths in life very well. Eventually convincing themselves that becoming chiefs and other leading officers would magically solve all their problems.