I was pretty certain it was going to happen sooner than later according to previous patch note descriptions and I assumed everyone figured it was going to happen sooner rather than later too. I had no idea the patch was going to hit mid-chapter though.
I believe most of the outrage is people wanted to keep their tanky thralls, but have accepted that it wasn’t going to be so they are venting their frustration on the specifics of a patch note instead. With maybe a small minority who haven’t been reading all off the notes previously.