Since so many did a fine job with your first question, I'll go with the more recent one. I happen to be ambivalent about military scifi. I don't seek it out, but I don't dislike it.
The reason I don't really seek it out (or anything that could be called military roleplay in a game or military fantasy) is because I'm just not really that interested in the military (on a personal level, I am thankful for the troops that help protect us). If I had to ponder the why, I'm leaning toward the story lines usually being too severe and strict for my liking. The characters all tend to be highly disciplined and strict/severe about things, emotional characters are portrayed as weak or lesser because they depend on the MC for survival even while they may have just as much to offer society even though they cannot really protect it.
I really like art and the whole image I get most of the time from military fiction is all about function, with which basic art forms jar (Or get exploded because there's madness all about and you're painting? WHY?)
I like functionality with appealing aesthetics. Also, in the visual world, where I encounter much of the military fiction stories I'm familiar with, the colour schemes usually lack vibrance and tend to be dull and dark. I get tired of looking at them.
I think it's far more than that though. I suppose maybe I'm just, on default, more interested in the art of life rather than the art of war. I say that last because I actually don't mind stories containing war. I read many stories that do, but it's part of the story, with maybe some characters in the military, but it's more about their lives, rather than centered on the war itself.
An immediate example that leaps to mind is Game of Thrones. There are a lot of military-involved (for the time period/technology of the world) scenes and characters, but it's more about their lives in those times than about the military or the war or their gadgets.
Plus, I'm just more interested in fantasy fiction and have several books waiting to be read that I already own (more that I want to own) so I only detour when something specific catches my eye from another genre.
Edit to add: Of course, some might define Babylon 5 as military scifi, I probably would, but ended up happily sinking into the story when my husband bought the box sets and started watching them. I can tell you exactly why it grabbed my interest: The rangers (fantasy like), Ivanova (strong female leader), and the psionics angle. I love supernatural/psychic/telepathic/telekinetic/etc. stories as much as fantasy ones. I mention Ivanova in particular, but I liked so many different characters in the series. Also, while some were strict/severe, including Ivanova, they were all more of a loose cannon too. I mean no offense, but my biggest reason for not joining the military when they were begging at my door was that I have a really bad habit of asking why, even when the order comes from a superior. If I cannot answer the why myself then I don't want to be responsible for the action I perform under the order. The crew in Babylon 5 pretty much did that as a whole. Lack of trust is listed as one of my weaknesses and (in many cases) the higher up the ladder you are, the less inclined I am to trust (had too many bombs dropped on me from above as a child).
I added that because, as an exception, I thought it might be helpful for you to know why I liked it when I generally don't give military fic the time of day.