I don't know for your country but in France, it'is not forbidden to marry a cousin. It is just recommended not to do it because there may be deformations ou disability in the child who will be conceived (Though, two men are not affected). For the fact that it is minors, it is true that they could have waited until they were of age to do it
Of course Direct family is prohibited. But no law prohibits cousins. It's disgusting between a parent and a child or a grandparent.
It happens that distant cousins get married without knowing that they are from the same family, when we know that for example my grandmother has 12 brothers and sisters whom I do not know I could marry a cousin without knowing it. Afterwards I find it weird but not disgusting.
A few years ago it was normal in noble families.
oooh cousins?? ANDDDD MINOR??? fuck this, dunno why its good, probably WOULD BE SO MUCH BETTER IF THEYRE JUST FRIENDS AND AT THE RIGHT AGE