> I'm glad she "married for love", but I don't see why it would be relevant
They're just making the point that she didn't marry him for his social credit score, even though he happens to have a high score under the system.
To quote the article immediately prior to that section:
"Who your friends and family are will affect your score. If your best friend or your dad says something negative about the government, you’ll lose points too. Who you date and ultimately partner with will also affect social credit."
It seems like your social credit score is positioned as your key to happiness. Better not get a bad one or associate with anyone who did. Better not wreck your child's future by saying something bad about the government.