OTOH, it’s probably no small part of why the civil rights struggles of the latter half of the 20th century were successful. The military was integrated post-WWII, and we had a lot of men who served in integrated units in the peacetime draft, Korea and Vietnam.
The trick would be to identify promising officers from the ranks; as the system stands now, it’s skewed toward middle and above people who can get college degrees, and due to the correlation between socio-economic status and race, that generally means white people.
But as to the OP’s question, yes, I think political echo chambers are terrible for society. I take my Dad as an example; he’s always been conservative, but between watching Fox News, and reading all the breathless glurge people send him, he’s far more polarized than he was say… 15 years ago. Basically he may get a notion of how something should be, and then the sources of information that he considers authoritative (friends, family, television news) reinforce that notion, and in many cases exacerbate it, and when friends/family have many of the same “authoritative” sources, it all sort of compounds itself, to the point where people really do believe that Obama is a muslim, or that the UN is trying to take our guns or whatever other credulous nonsense is making the rounds.
And I’m sure the flip side happens on the democratic side; I see it happen around here all the time. Certain things are taken as God’s own truth and self-evident, and any dissent or disagreement is shouted down as heretical.
It’s not ignorance on either side; it’s merely a lack of reasonable challenge. And the TV shows don’t help- they tend to have debates between people who are 180 degrees off from each other in viewpoint, in order to generate some good Jerry Springer-ish hollering at each other, rather than getting two people who are about 30 degrees off-center either way, and having them have a good, respectful, productive debate.
Probably the worst single effect of the echo chamber/polarization is the notion that “you’re either with us or against us”, as if Armageddon is imminent. There’s no room for the middle anymore; if you’re stupid enough to get into a political discussion these days, and you’re centrist, you find yourself fighting both sides.