I think the romance scenes in this game are silly as well, but to insinuate that anyone that likes them is a child/teenager IS indeed an insult.
I insinuate that this is teens level ideas of romance and sex in a video game. Its more funny that anything. Everyone is laughing at these scenes in nearly all social content. Not seing anyone cry and gasp over the incredible emotional impact and deep storytelling of these engrossing scenes.
That particular scene was never designed for or intended to display a deep emotional attachment or actual romance...it's literally just a fling. That is something that isn't all that unusual between people. People often sleep with relative strangers, or people they haven't known for long, just because they want some sex. You mistake this for the romance of the game when it is not, that might come much much later in the game than act one but this isn't it. This is literally just a fling, it's not that serious.