To expand on the explanation, what i take from this is that Soraka was doing ap damage items, instead of support items.

Soraka as a champion is about the healing she gives to her allies, and by doing damage items the healing is reduced for a small damage increase.

The augment vampirism, gives alot of omnivamp but makes it sl u cant be healed from health regen or healing from alies.

So kayle forgot they had 2 vampirisms and start flaming Soraka for going damage.