All of that may be true, including the NC player getting a piece of the ball. But none of that changes the fact that this was a reckless slide at full speed into a player from a bad angle. With cleats clearly up. Straight red worthy, IMO.
When I played, the slide tackle was my favorite move. But I never went in with a slide tackle where the other player didn't see me coming. Always with the ball between the other player and me. Never with the player between me and the ball, even if I thought I could get a piece of the ball. And never ever with cleats up. You can slide tackle and still be responsible and careful. I'm not saying the NC player made a dirty play, but it was definitely done without care or concern for a player who she was blindsiding. A yellow is not a sufficient deterrent for such a play.