That graphic makes him look pretty good, no? Excellent defensively and passes the ball very accurately. Kind of what you want from a DM.
There are some key qualifiers to him being "excellent defensively" - you can mainly see that in his mediocre overall "Threat Prevented" measure. This suggests that the above average tackles he does make are in relatively insignificant situations in the game, e.g. in a scramble on the half-way line. It suggests that he is actually sub-par in making defensive contributions in key circumstances, eg when the opponent is ready to shoot inside the box, or has played a dangerous cross in to the box. You can also get a sense of this from the fact his Shots Blocked stat is pretty much bottom of the pile.
In a nutshell: it shows he does his ball winning chasing up the pitch, but is poor when on the back foot and it really matters (eg if under pressure trying to prevent a goal).
His bottom-of-the-pile 'Threat Created' and 'Progressive Passes' stats also point to the fact that he is basically a passenger on the ball, and at best will play a simple pass backwards to expect someone else to make something happen.
Him being poor defending the box and poor utilising the ball means he's ultimately poor at the two main scenarios you'd likely want to use him in:
1. You are pushing to win the game (whether it's 0-0 at the start of a match, or you're a goal behind later on etc.). Having one of your midfielders who is so incredibly sub-par at making things happen with the ball is not going to increase your chances of scoring a goal. It's close to having 10-men when you're in possession of the ball.
2. You are already winning and wish to defend that lead. Having a central midfielder sub-par at defending the box under pressure is not going to increase your chances of preventing a goal. We've already seen this time and again for United, where the midfield falls apart whenever Casemiro is subbed for Ugarte. It's as if Ugarte manages to be everywhere on the pitch except for where you need a DM to be.
Again, you can also get a sense of this from his overall "Player Impact" rating of a meagre 10th percentile. Ultimately, he has very little impact on the game at either business end of the pitch.