The sacraments are divine. The annulment, an earthly convenience. The process has a religious pretension, to make it palatable, but an earthly convenience it is.
The four criteria are supposedly affirmed during the sacrament - you can’t just rely on the “honor system”, and Catholics do not.
Regardless, sometimes people can’t live together regardless. Catholics need their way out, and they have it. I’m not arguing against it, just against the presumption that it is somehow more legit than any other garden variety divorce for “irreconcilable differences”. It’s a process Catholics have invented for themselves - which is fine.
Matthew 16:19 I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.”
“Immaturity” seems to be a catch-all for annulments; since it has to be something at the time of the original marriage that invalidates it/gives cause for an annulment, immaturity is an unverifiable catch-all (not as concrete as a pregnancy or prior marriage by one party) that seems to work.