Really telling how much you're reading into this. I wonder what your opinion would have been if you had not seen the editorial bit at the top, only the cartoon. I feel both you and OP are looking for offense when I feel there is none to be had.
Again, if the artist wanted to portray flappers as unattractive, a poor option for a marriageable young man, he could have easily depicted her as sickly and gross. If anything, it's almost like he's making fun of the demure, old fashioned girl. But that's my modern sensibilities and attractions speaking. :)
BTW, flappers were a sort of 1920s women's subculture. Google it and hit "pictures" and you'll instantly get the look. They were young rebels, breaking out of the female mold they had been forced into. For example, women simply did not smoke before the 20s, strictly a male thing. Not sure if this was an American culture or if the Europeans shared, or likely, started it. From what I gather, flappers were pretty common, nothing weird at the time. 🤷