if the adults come to you for food the babies will be all over you, literally they don't know they are supposed to be afraid of you so they will land on your lap or sit on your feet, sometimes in fly straight into you so damn cute.
They are cute not my experience at all with the 40+ jays i have visiting me daily. The only animal i have witnessed jays attacking is each other, in breeding season, over food. the starlings i have in my yard are far more aggressive then the steller's jays. that being said cats are predators and during breeding season almost every bird species will attack or harass cats and other predators that come within range of their young. I've seen swallows diving red tails and blackbirds plucking feathers out of eagles. It is survival for the birds, they know as well as we do that cats will kill their young at the first opportunity.
All birds are individuals though and my old cat whose bird killing days were long gone was never once attacked by our jays, and only mildly harasses by our crows the birds were very apt at making a threat assessment and decided he was not one. unfortunately this created a bit of a problem i am trying to undo because the birds are far too relaxed around any cat that enters my yard now, and i have to spend my days watching out for cats and chasing them from my yard.