Probably because Rosey has used up all his whinging credits about mundane things, so now there’s actual things to complain about they’ll just shut the door on him and give him a fine.
This is undeniably true, and yet at the same time, I think you do see this exact thing happen every so often and I wasn't at all surprised at the time, even though I could clearly see it was a deliberate elbow.
There was a potentially third red when their player already on a yellow delayed a throw in. At the start of the season that was an automatic yellow, and a second yellow is still a yellow last I checked.