Some reject God's wisdom, but true followers embrace it, no matter the disguise.
Jesus uses the illustration of children playing to show a fundamental difference: some children will play any game, while others refuse. The ones who will play are described as 'Wisdom's children.'
This means that those who truly belong to God, those who are genuinely seeking Him, will recognize His wisdom when it appears, even if it comes in unexpected forms. They don't get stuck on the packaging.
When John the Baptist came, living an austere life, they said he was demon-possessed. When Jesus came, eating and drinking with people, they called him a glutton and a friend of sinners. Both were God's messengers, sent by Wisdom, but the critics couldn't see it. True followers, however, 'are justified by her children' – they recognize and affirm God's wisdom, whether it looks like John's desert austerity or Jesus' relational ministry.