Why the obsession with fat in breastmilk?

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I see this all over instagram. For those who pump and put milk in fridge, the milk separates and the thick fatty layer rises to the top. Everyone's obsessed with showing how fatty their milk is...or the thick "milk plug". Many women are even searching for products to increase the fat content in their milk. 
I'm just sitting here wondering why? Your body makes exactly what your baby needs so why the obsession to alter your breastmilk? I don't have a super thick fat layer when my milk is refrigerated and my baby is a happy CHUNKY baby. 
Am I missing something? Please help me out. Why does everyone wanna increase the fat in their breastmilk? Is there some benefit I'm not aware of with fattier breastmilk? Doesn't the body make exactly what your baby needs?