The study was talking about 300 000 children being married. That's not a few.
And 1321 of them were 14 and younger.
That's 300k and 1321 respectively too many.
And apparently, at least for some republicans, this is a policy worth fighting for: https://www.google.com/amp/s/www.businessinsider.com/mike-moon-gop-missouri-lawmaker-defends-childs-right-to-marry-2023-4%3famp