i don't think he was intentionally doing it. he probably cut into the turn early just like you, using your line as a guide for himself, and then found himself out of control just like you. at that point you're jabbing the wheel right as he's sliding into your blind spot and you turned into him right when he was on your rear panel.
he shouldn't have been there and he should have held a consistent radial line around the turn instead of throttling trying to outpace you despite sliding further outward towards you.. but for the collision, in the specific instance you happened to yank the wheel right to save yourself, as he was overlapping, the system detected your momentum hitting him (watch the camera jerk right repeatedly before impact, the SR system would sense that movement as you turning into him)
it would be great if the system would evaluate traction ratios into penalties, as the other guy could have easily eased off of the throttle to avoid the impact
as for you, there was a guy behind you on the straight. once you blew the turn and were scrubbing tons of speed squealing away from the apex... I would have expected somebody faster ramming into me and let my car stabilize on the furthest edge of the track to avoid getting punted until i could safely re-approach my usual line.
this turn by the way, is where i do most of my passing. everybody cuts early and ends up swinging mid to outside of the track.. so i ride up onto the curb, lift off of the throttle, and then enter the turn at half throttle cutting fast and into the inside passing everyone. it's a good turn to master.