A "cartel of 4 big clubs" composed of Real Madrid, Juventus, Bayern Munich and FC Barcelona pressured UEFA with threats of "Super League" to make France lose slots in UCL and to guarantee 4 slots for Spain, Germany, UK and Italy - #FootballLeaks
These 4 clubs are looking out for their own interests. They want to virtually guarantee that they themselves will always have a slot in the CL every year. Obviously it would look very weird if those 4 clubs got guaranteed 4 slots or the Italian, German and Spanish got guaranteed slots without also giving it to the Prem.
So by saying Top 4 Leagues, they disguise that that this rule change was from pressure from these 4 specific clubs.