It's understandable to be dissatisfied; it's definitely not the kind of story that gives a comfy closure, but it's a one-shot. This is hard to explain, but if this chapter took place in just any random larger story, I would be less compelled to defend it, even if I'd still probably take note of some possibly romantic tension. But what we see here is what we get, incomplete as it may be. To me, that puts the story in a different context, which makes the tension seem more important, and its nature seem more romantic.
This is all a very personal thing, so I don't expect anyone to agree, but this is one way to read this short. I think both the Subtext and Yuri tags would be fine; in this case I assume the latter was picked because of the magazine that published it. I wouldn't say the fact that it was published in a yuri magazine makes it yuri, but it does count a bit, at least to me.
Neither of the girls seem to have actual romantic feelings for each other.
Misora definitely seems like she's crushing on Mame.
One of them has a soon to be boyfriend.
That sounds like an exaggeration. She was excited because someone asked her out. For all we know, Mame walked home with that guy once, and that was it. She even says she just sees him as a friend.
Interesting, I'd like a sequel for this
Considering that this was published like 6 years ago, that the author doesn't seem to be very active, and that I can't find any other yuri work from her anywhere, this might not be very likely.
Agreed. Many comments here don't seem to notice the obvious romantic feelings she has for her. Debating whether this is yuri or not is kinda a waste of time for everyone honestly, especially when there's scenes that supports the notion of this being yuri.