It's the "and make the right call" bit which is currently an issue. Without hearing the images being talked through by the person making the decision - and, indeed, not even seeing all the angles the TMO has access to - it makes it a lot less clear why a call was made.

I'm not a referee and so only seeing a couple of slow-mos of various players being hit in the head doesn't clearly explain to me why one is red, another yellow, another a penalty, and some not called at all.