Because Kinetic batteries are just standard lead acid batteries. They just use AGM technology instead of the old flooded cells.
Lithium batteries don't charge or discharge at the same rate as lead acid batteries. Ever notice how your drill with a lithium battery goes from having plenty of charge to being dead in like 10 seconds? Lithium batteries don't slowly drain down like lead batteries do. And they charge at a different rate as well. Those differences in charging and discharging rate plus the fact that lithium batteries are inherently unstable makes them incompatible with regular lead batteries of any kind.
I have since spoken with Lithium LifeP04 Suppliers & users, & THEY DO RECOMMEND USING THEM IN THE SAME CIRCUIT AS AGM BATTERIES. I AM CONTEMPLATING ADDING THE LARGEST LIMITLESS IN PLACE OF MY KINETIK HC1800, while keeping 270AH Agm capacity plus the limitless (80 REAL AH)