This is not a defence of Fred, as he is truly awful at most aspects of the game, but, I think he's made to look worse than he is by his good positional sense/being full of running. He reads the game well enough and has enough positional sense to get himself into the right place to make a play. Fred's problem is that he consistently fails to make that play and therefore puts himself centre stage when he fails to control a ball/misplaces a pass/misses a tackle/gets dribbled by etc.
Compare that to McTominay for example, who isn't always in the right place to begin with, and therefore can't look quite as bad.
I also think his positional sense is why Ole keeps picking him over say, VdB who he can't trust to be in the right positions.