The one thing that always bugs me about the "yukkuris are living things" argument? Being living things doesn't matter. The bubonic plague is a living thing (look it up, it's bacterial in nature), and we sure as hell don't purposefully let the bubonic plague spread out of misplaced sympathy. No, we stomp it out. Because its existence is harmful to us.
Trolling his yukkuri fatally? In my experience with images on this site, abyusive owners tend to go for some real misery instead of such a quick (albeit painful) kill.
Even discounting the stuff in Yukkuri Bonsai, mamumamu-vs.-elsewhere doesn't do much to explain why yukkuri couples who refresh consensually for the hell of it pretty much always wind up with stalks (and panicky cries of "WHY ARE THERE BABIIIIES?"), while post #13835 has a Reimu churning out mammalian births that are most assuredly getting their daddy-paste from somewhere else, and post #22556 has a Marisa spawning kos by both methods at the same time from getting Alice-d in a single point.
By which I mean, there wouldn't be a difference in the "stalk-type" and "mammalian-type" stuff and thus no need to market them separately. Sorry for doubleposting, just realized I was badly worded and wanted to clarify.
I'm still going with the explanation of it being something the "father" does to the reproductive paste. Elsewise, there would be no way for post #12026 's bottled mammalian-birth filling to exist.
I'm still gonna point at post #12026 every time the location idea of determining births is mentioned, since the existence of an extract that can cause mammalian pregnancies kind of does poo-poo all over the idea.
^Nah, if all it took to make 'em starve to death was two kos (and it almost certainly was starvation, given the sunken cheeks) there wouldn't be any Patchoulis. I mean, Patchoulis may get husbands a lot, but what yukkuri would ever consent to being a Patchouli's wife? Such would be a surefire recipe for disaster, and thus for no more Patchoulis.
In other news, I'm thinking *way* too hard about yukkuri population sustainability.
It's probably for the same reason that pulling out doesn't stop humans from making babies. Alice had some custard just slacking off on the tip, not enough to see, but enough to kill little Marisa.