You shouldn't concede goals at set pieces. Why not, it is a chance for the opposition to hit the ball into your box at pace with several players attacking it. The fact that all corners/free kicks regardless of the taker are treated the same is mental, and a real Sunday league football thing. KDB, Junihino, Pirlo getting a free kick is not the same as Triggs from the dog an duck hoofing into the box.
Specialist midfielder, usually the holding role. This is basically a let off for a lot of average players who aren't well rounded to just sit in front of the back four and shirk offensive responsibility. I'm not including the likes of makaele btw, but some players (Jordan Henderson) who have are lucky this thinking exist.