How do you figure? People who are investigating and want the investigation to continue, want to be able to do exactly what you suggest. Follow the facts and find out if he is guilty. I hear NO ONE accusing Trump of collusion. NO ONE. Mueller was definitive on this issue and everyone accepts his findings.
The problem here is that Mueller also listed 10 instances where Trump obstructed justice. THAT, is why people want to use the American system of justice and follow this to the end.
I would also say that if it is found he did not obstruct justice, I for one would be okay with that. Barr's poor attempt at fudging the facts, just makes the entire administration look more like a banana republic.