Judging fashion

Can someone please explain to me the current trend of ladies wearing pants that are several inches too short with boots?  I'm sitting in the walkway between terminals at the airport with a delayed flight, watching the people walking by and coming out of the Sky Club, and at least half the ladies have several inches of bare skin between their pants and their boots.  I understand capris or rolled cuffs in the spring or summer with sandals or sneakers or heels... but if it's cold enough to wear boots, isn't it cold enough to wear socks and pants that don't, you know, look like you bought them in the fifth grade? (I say this as someone who still wears a pair of jeans from the fifth grade and many of my middle school clothes....  But then, I haven't grown since then.)  Perhaps my problem here is that I don't understand trends.  I was, after all, a big fan of cozy long sweaters with colored skinny jeans as a child and, with the help of my mom's wardrobe, rocked that look all through lower school despite it being as far from on-trend as could be.  I remember that the black-with-white-stripes Adidas were a big thing at my school. All the cool girls wore Adidas.... Why?  Were they comfortable?  Did they go with more things?  I thought they looked a lot like my grandma's orthopedic shoes and wore my rose-print-covered fake Keds instead.  The only trend I remember jumping on board with was bike shorts under my skirts.  Because duh, clearly that made sense.  How's a girl supposed to hang from the monkey bars without bike shorts??

But the too-short pants with boots thing... Really don't get how this became a thing.  Is it like air vents for your knees?  Is it an evolutionary thing where by displaying that the woman has outgrown her pants, she is signalling her growth genes?  This must be it, right?  Because it violates the cardinal sin of women's fashion by chopping up the leg line weirdly, so it's not about making women look better, and surely thousands of women don't buy too-short pants either just because they were in some runway show or because when some company got in an order of their imported pants from China they discovered they'd been manufactured in Chinese sizing and didn't want to waste them and so declared it a trend....  Right?

No, surely they're both comfortable and practical.  I'm going to go with the air vent and evolutionary growth genes answers.  But I'll also continue to look silly and off-fleek ("on fleek" is the trendy term for "trendy," right?  Or is "on fleek" off-fleek by now?) with my 32-inch-inseam pants.  There's probably some girl writing a blog judging this choice right this moment....