Not even as a different society (it’s still wrong btw, even in that society, since they were Anemone to become an adult), old monarchies had this happen occasionally and it led to the kingdom having a shit ton of problems. People married the children of royalty (most of the time it was some old dude marrying either an extremely young women [18-19 years] or even children [13]) or were arranged to be married (appears to be the situation we see with Whirlpool and Anemone and was more common) from a young age to an older guy to get to the throne, often in exchange for alliances and trade agreements. Nations that did this were usually extremely close and did it to strengthen their relationships. Sometimes it’s abused to get into power (the way we see Whirlpool using it).
I’m pretty sure this was what Tui meant by when this was written, while at the same time warning the reader not everyone is who they seem to be. We see early on the Whirlpool has a lot of influence, was often strange or off-putting in a way that made us not want to trust him or know something was off, and by the end of the book it was mask completely off before Anemone promptly kills him. However, any argument made to say that he was a good villain for trying to abuse a legal way to get into power is going to be overshadowed by “bro tried to marry a child.” Again, I’m pretty sure this is why Tui avoids him and why this and similar situations never touched again. It’s usually a hostile takeover situation whenever power comes up.
