Mueller didn’t have sufficient proof to conclude that the president committed any crime including obstruction and chose to smear the president saying “If we had confidence the president did not commit a crime we would have said so.”. If the president or anyone would say:
“If we had confidence that Mueller did not commit a crime we would have said so.”that might be a valid statement as well.
Basically anyone can say it on anyone that for making a smear. This shows Mueller bias and unprofessional conclusion. If sedition laws were in place Mueller would have been in legal trouble.