How did it nerf BoRK ADCs? IIRC, most champions who might rush BoRK (Vayne, Twitch, Kog'maw) didn't get Infinity Edge second anyways, instead opting for Phantom Dancer, Youmuu's Ghostblade, or Trinity Force in most situations.
The change only really affected champions who would rush Infinity Edge and Statikk Shiv. And considering Statikk Shiv was pretty much always picked over Phantom Dancer, it isn't really a bad change.
Anyways, Riot stated their reasoning and intentions pretty blatantly in the patch notes, so I'd recommend actually reading those sections if you want to know why they made the change.