When I went back and watched it, the receiver gained separation (albeit, not much... but enough needed) by extending his arm. Calhoun wasn't beat because he was on his hip pocket, separation happened, catch was made, and Calhoun closed the distance after the catch and made the tackle. It was ticky tack... and I might be a little pissed if that was us, but there was justification there for the call and the official made the call.
The other calls were completely and totally correct. Don't know why you'd ***** about those?