Stretch is an interesting, and trickier, one. It was first serialized in a seinen manga, which doesn't preclude yuri but does explain the fan service. Then it moved to online only on Shou's site. So the demographic was limited to Shou's site traffic and, well, us on DS, kind of. We're more inadvertent though.
I think authorial intent might play in more because demographics and the market are dead ends (or just seinin) this time. Considering Shou's previous, and concurrent with Stretch, work in comic Lo, there's a lack of yuri all around. Though there is romance? It comes down to how intentional the imagined relationship between the pages is, which makes intent hard to find without some serious close reading. Shou knows how to yuri, but they don't seem to be doing it this time. A closer look at the ending will likely color the whole series by sucking the legitimacy out of a potential relationship, but I can't be sure without a rereading.
Well, does it follow established yuri patterns and meet the looser definition of an intense platonic relationship between women? I think that was one of Erica Freidman's definitions. One particularity tricky wrench in the system is that the backstory is set up like the archetypal yuri story of girl falls in love with girl who was in love with her the whole time.
I think that's where the ire against the story comes from. In yuri, those flashbacks of when they knew each other in school would imply the beginnings of romantic interest. In, say, yuri hime. Or, by a known yuri mangaka...