I'm really not familiar with this 'rule.'
In BvS, Diana took on Doomsday, the creature that killed Superman, without a scratch and, if Clark hadn't been bent on martyrdom, probably could have killed it with that spear and survived.
But there's no doubt Diana came out on top of that exchange as she hacked bits of it off, so Diana>Kryptonian hybrid Superman-killing beast
Thing is, in JL2? Diana could come out of the gate and beat Superman, so then she wins and if JL2 does better at the box office then Diana>all Kryptonians?
I'm not buying this particular rule.
Add to the fact the ridiculous inconsistencies in this movie (Diana speed feat at the opening of the movie, Diana not able to move during speed combat later. Superman able to resist the irresistable magic lasso, etc.) plus the fact that it was critically panned by professionals and fans alike and made the least amount of money (was seen by the least amount of people) then Wonder Woman>Doomsday>Kryptonians by virtue of more people saw her kick Doomsdays butt than saw that goofy fight in JL
Not to mention Diana was completely uninjured and fine at the end of that fight. She held him with the lasso, head butted him right back and then...vanished from the fight with Flash before Lois ended everything.