Child beauty contests are completely harmless. Their negative impact is in no way greater than anything competitive sports does to children. People, however, need to do tons of virtue signalling, so they scream about the terrible "sexualization" going on there, when it is in fact just some kids playing dress up, one of the most natural games children play.
Speaking as a psychologist, you really need to be squinting to think like this. Consider motivations for entering into such a contest and who they're held by.
What do we need arguments for, mate? It's been talked about a thousand times. It's bad, it HAS horrible psychological effects on kids and it IS sexualizing them. You're wrong just to be contrarian. It's annoying. It's not Kids playing dress up, it's that while they are getting rated (eeew) by adult people.