Perhaps; the sense I got from those articles was that young women (“debutantes”) were affecting a slouchy posture in the 1910s, which other, more uptight (i.e., older) people thought was untoward and not feminine-looking – the “that could become dowager’s hump!” caution in the one article feels, to me, like a scolding/warning, which may not have had any solid evidence behind it, that that particular behavior could have unwanted consequences later in life.
They aren’t quoting doctors or medical professionals in those articles – the first one mostly relies on opinion from a physical education director at a local YWCA branch (and has all sorts of other, “interesting” opinions on how tight skirts and pointy shoes make your face ugly), and the second one seems to be just an unattributed opinion piece.
It feels akin to “warnings” like “if you sit too close to the TV, you’ll go blind!”, or “if you crack your knuckles, you’ll get arthritis!”